The Fallacy of the 2-Metre Rule – Part 2

Read part one of this blog post here.

Aerosol Transmission of Covid: More Prevalent than Presumed

For months into the pandemic, the World Health Organization (WHO) and U.S. Centers for Disease Control and Prevention (CDC) insisted close-range, large-droplet spread was driving the pandemic. Aerosol transmission, WHO stated, was limited to “specific circumstances and settings,” primarily aerosol-generating medical procedures such as intubation and CPR.

Prodded by scientists worldwide, both organizations eventually agreed aerosol transmission of SARS-CoV-2 was possible in community settings and perhaps not rare. But even today, top scientists warn the impact of long-range spread has been vastly underestimated.

“Aerosol transmission plays a significant role in indoor environments and cannot be neglected,” argues Maosheng Yao, PhD a professor of engineering at Peking University.

Covid transmission via aerosols “matters much more than has been officially acknowledged to date,” agrees Linsey Marr.

In reality, transmission via large-droplet spray, like transmission via aerosol, requires its own “special circumstances and settings” — for example, standing before a Covid-infected person who just sneezed.

There’s no evidence that close-range, droplet transmission is the primary driver of Covid spread and much to suggest that it’s not.

For one thing, asymptomatic and pre-symptomatic people account for at least 50% of all transmission, according to the U.S. CDC. In other words, they’re not sneezing or coughing up phlegmy, infectious gobs — the kind those plexiglass dividers are designed to contain.

What’s more, careful studies of super-spreading events have found long-range aerosol spread responsible for large numbers of infections.

For example, an analysis of the Diamond Princess cruise ship — where 712 of 3,711 passengers became infected — estimated that short-range transmission accounted for just 35% of cases. Another 35% were attributed to long-range transmission and 30% to spread via contaminated surfaces.

Then there’s the infamous American choir-practice case, in which a single infected singer transmitted Covid-19 to 53 of the choir’s 61 members. Scientists interviewed the entire choir and analysed their seating arrangements and movements throughout the 2.5-hour practice.

While it’s possible some members became infected at close range, inhalation of aerosols from shared air was “almost certainly the leading mode of transmission,” the study concluded.

No choir member sat within 3 metres in front of the infected singer, and four singers who contracted Covid sat behind the singer. For them to have become infected via large droplets, those infectious gobs would have had to travel backwards, a physics-defying scenario in a room with poor ventilation.

American chemist Jose Jimenez, who interviewed the choir, says one member contracted Covid despite remaining 44 feet (13.5 metres) from the contagious singer.

All the evidence taken together, says Jimenez, “convinced us that only airborne transmission could explain this case.”

Restaurants and shops worldwide have reduced occupancy, on the theory that spreading out patrons would control Covid spread. But without other precautions in place, such as air dis-infection, reducing capacity won’t suffice. Occupancy in sections of the choir hall ranged from 44% to 55%.

Those ubiquitous plexiglass dividers won’t help much, either.

As part of his research on Covid spread, California scientist William Ristenpart investigated transmission at a karaoke bar. After an initial outbreak, the owners installed plastic partitions in front of the singers.

“But it didn’t solve anything,” Ristenpart reported at the international Covid-transmission workshop. “Another 18 people got infected. It’s more indirect evidence for this idea of long-range aerosol transmission.”

Covid Will Fade, But Aerosol Spread Won’t

Ultimately, it doesn’t matter what percent of Covid cases are spread via large droplets or tiny aerosols. We know aerosol spread happens — often.

And those responsible for the safety of indoor spaces must take heed.

As the Diamond Princess analysis noted, the cruise outbreak underscores “the importance of implementing public health measures that target the control of inhalation of aerosols . . . not only aboard cruise ships but in other indoor environments as well.”

Which measures target aerosol spread best?

Certainly, mask mandates help. “But even with the masks, you have leakages of particles,” Lydia Bourouiba of MIT said at the Covid workshop. “The aerosol spread will be slower, but aerosols will still accumulate.”

Even universal masking wouldn’t halt transmission. “In Hong Kong, we’re very good at wearing masks, but we’ve had two community epidemics in spite of more than 99% of adults reporting wearing face masks in public,” says Ben Cowling, PhD, a University of Hong Kong epidemiologist.

At any rate, masks are not a long-term solution to aerosol spread of disease.

When the Covid pandemic fades and masks are tossed, infectious microbes will still be swirling around. These pathogens include influenza, which, like Covid-19, can be transmitted by both aerosols and large droplets.

What’s needed indoors are increased ventilation and air filtration, as well as continual, medical-grade air disinfection, such as NanoStrike technology, developed by Novaerus.

As independent laboratory tests confirm, plasma generated within Novaerus units obliterates airborne pathogens of all types: viruses, bacteria, and fungi. Instantly, virulent particles are reduced to inert debris.

Novaerus units accomplish this without emitting harmful byproducts and have proven safe for 24/7 use around even the most vulnerable patients.

Throughout the pandemic, the compact, unobtrusive devices have been running in hospital Covid wards, emergency rooms, and operating theatres, protecting staff, patients, and visitors alike.

Now that the pandemic’s end appears within sight, the same technology is being installed by pubs, restaurants, pharmacies, retail shops, offices, and schools. The goal: to fight Covid, influenza, norovirus, and other pathogens, current and emerging, that can and will spread infection.

We can’t remain 2 metres apart forever. And as science now demonstrates, standing 2 meters apart won’t stop aerosol spread, anyway.

Novaerus Defend 1050 cleared by FDA as 510(k) Class II Medical Device

Novaerus Defend 1050 cleared by FDA as 510(k) Class II Medical Device to inactivate and filter out airborne virus and bacteria for medical purposes

Defend 1050 uses patented NanoStrike® technology to damage and inactivate airborne micro-organisms.

Dublin, Ireland and Stamford, CT – Novaerus, a WellAir company that delivers clean air solutions to help prevent the spread of infectious outbreaks, announced today that the U.S. Food and Drug Administration (FDA) cleared the Novaerus Defend 1050 (NV 1050) as a 510(k) Class II Medical Device to inactivate and filter out micro-organisms, including virus and bacteria, for medical purposes. The Novaerus Defend 1050 is the first system that uses NanoStrike®, a patented plasma generating technology, to receive FDA 510(k) clearance.

The Novaerus Defend 1050 is a free-standing, portable recirculating air cleaning system designed for additional frontline protection in healthcare settings such as operating rooms, intensive care units, in vitro fertilization labs, emergency rooms, waiting and treatment areas, neonatal units, and other critical environments including those performing aerosol-generating medical procedures (AGMP).

The Defend 1050’s NanoStrike technology uses a plasma field that rapidly inactivates micro-organisms at the molecular level. Within 15 minutes, the Defend 1050 has demonstrated a 4-log (99.99%) reduction of the MS2 bacteriophage RNA virus, an accepted surrogate for SARS-CoV-2. The Defend 1050 also showed a 4-log (99.99%) reduction in Bacillus Globigii endospores (bacterial spores) within 15 minutes, which was maintained over the prolonged operation (24 hours).

The Defend 1050 is currently used in hospitals and healthcare settings worldwide. Given the rapid spread of COVID-19, WellAir moved quickly to understand how this device could potentially combat the virus while moving it through a thorough FDA medical device clearance process. Additionally, the Defend 1050 meets relevant performance criteria in the FDA Guidance, which provides non-binding recommendations that may reduce the risk of viral exposure for patients and healthcare providers during the current public health emergency.

“Our team of outstanding engineers and scientists have been focused on delivering innovative and powerful airborne infection control devices. The FDA clearance on the Defend 1050 is a critical milestone for our company, validating our work to deliver a safe and effective medical device,” said Dr Kevin Devlin, WellAir CEO. “The Defend 1050 has demonstrated tremendous efficacy in third party testing against viruses, bacteria, VOCs, and particulate matter, which makes it an ideal solution for hospitals and healthcare settings. As we continue to see an alarming rise in the number of COVID-19 cases, we have moved quickly to make the device readily available.”

Defend 1050 utilizes multiple stages to reduce airborne micro-organisms. The first stage is a general air pre-filter that captures particles between 4 and 10 microns from the input airflow. This filtered air passes through a series of NanoStrike coils (plasma generators) that damage and inactivate micro-organisms on contact, including viruses and bacteria. The resulting inactive particulates are trapped by a HEPA (High-efficiency Particulate Air) filter. In a final cleaning stage, an activated carbon filter traps VOCs in the airstream before the air is released into the environment.

The Defend 1050 system is delivered complete with all components necessary for immediate use. It can be wheeled easily by a single person to the desired point of use and plugs into standard outlets. Five airflow speed settings enable optimization to each healthcare environment. The only routine maintenance required is a calendar-based filter change schedule.

If you are a medical or healthcare facility interested in learning more about the Novaerus Defend 1050 or other Novaerus products, additional information can be found here, or please contact Novaerus.

Air Dis-infection: A Potent Weapon for Averting a Covid-Influenza “Twindemic” – Part 2

Read part one of this blog post here.

Flu Virus Hovers in the Air

For decades, scientists assumed influenza was spread only by large droplets and by touch. For example, an infected person coughs or sneezes, spraying gobs of virus that land in the mouths or noses of those nearby. Or, those hefty, virus-laden particles settle on a surface touched by people who then touch their own mouth, nose, or eyes.

But in recent years, we’ve learned that influenza can be transmitted via aerosols, much smaller particles that linger in the air and can travel longer distances. (We’ve learned the same, in far less time, about like SARS-CoV-2.)

“Aerosols play an important part in the transmission of flu viruses,” observes Australian virologist Ian Mackay. “Virus can be recovered from asymptomatic folks, and breathing and talking are the likely ways transmission occur before anyone around us knows we are sick.”

Not only can influenza aerosols travel farther than larger droplets, but they may also be more infectious.

In an intriguing American study, scientists collected breath samples from 37 confirmed influenza patients who were asked to cough periodically into a cone. Some 43% of the volunteers emitted large particles (greater than 5 µm) of detectible viral RNA, and 92% exhaled aerosols. The interesting part: the aerosols contained more flu virus than did the larger droplets.

The authors concluded: “The abundance of viral copies in fine particle aerosols and evidence for their infectiousness suggests an important role in seasonal influenza transmission.”

Just how important a role? A University of Hong Kong team, studying influenza transmission in households, concluded that aerosol transmission accounts for “approximately half of all transmission events.”

Compared to a flu case transmitted via droplets, a case transmitted via aerosol appears “more likely to manifest in fever plus cough,” the Hong Kong scientists wrote.

Can masks mitigate the spread of influenza, as they do SARS-CoV-2? Absolutely, but aerosols still slip through masks, and despite the surging threat of Covid-19, mask-wearing among the general public is low.

When the Americans coughed into the cone while wearing surgical masks, they emitted three times less viral aerosol than when they coughed maskless, but 78% of the volunteers nonetheless emitted virus-laden aerosols.

Another American study, simulating influenza spread in exam-room conditions, found that surgical masks blocked the entry of 56.6% of infectious virus.

Flu particles generated during coughing, sneezing and breathing, the authors concluded, “is a concern in healthcare facilities because these particles may remain airborne for prolonged periods. Anyone present in a room with a patient who has influenza might be at risk of exposure.”

NanoStrike Technology: A Hedge Against Fatigue and Apathy

Mass flu vaccination, mask-wearing, and social distancing — this trifecta would go a long way toward averting the feared twindemic. But resistance to these measures is on the rise.

Sacrificing our normal routines “has exhausted us all,” observes Dr Hans Kluge, the WHO’s regional director for Europe.

In the eurozone, about half the population feels “pandemic fatigue,” says Cornelia Betsch, PhD, a German professor of health communication. In the United States, resistance is even stronger and more widespread. Citizens are flocking to bars and gathering with family as if Covid-19 did not exist.

What this means: medical facilities, schools, and workplaces must adopt virus-control strategies that are not compromised by human indifference, fatigue, or defiance.

Among the most important of these strategies is air dis-infection, particularly the ultra-low energy plasma technology, known as NanoStrike, used in Novaerus devices.

These compact devices generate an electrical discharge that destroys viral and bacterial particles. Within nanoseconds, the particles explode into inert, harmless debris, and clean air is expelled back into the room.

Independent lab tests have confirmed the technology destroys influenza as well as MS2 Bacteriophage, a virus used as a surrogate for SARS-CoV-2.

Unique among air-disinfection devices, NanoStrike technology leaves behind no harmful by-products. Novaerus units are so safe that they are commonly installed in hospital ICUs, Covid wards, operating theatres, and emergency rooms.

Schools, pharmacies, pubs, and numerous workplaces find that installing medical-grade technology instils confidence in staff, students, and patrons.

We know most transmission of Covid-19 and influenza happens indoors, and significant spread is due to respirable aerosols that can travel beyond 6 feet and linger for long periods.

We know, too, that people are just plain tired of taking precautions.

“In the spring, it was fear and a sense of, ‘We are all in it together,’” says Vaile Wright, a psychologist at the American Psychological Association. “Things are different now. Fear has really been replaced with fatigue.”

Given this fatigue, along with the absence of a Covid vaccine and the obstacles to widespread flu vaccination, workplaces of all types must continually dis-infect the indoor air we all share.

Air Dis-infection: A Potent Weapon for Averting a Covid-Influenza “Twindemic” – Part 1

For months, global health experts have feared the collision of Covid-19 and the seasonal flu. But now, with flu season nearing and Covid-19 surging, averting a “twindemic” appears more challenging than initially predicted.

The coronavirus has rebounded across Europe and continues to rage throughout the United States, overwhelming hospitals in many regions. Pandemic fatigue has set in on both continents, escalating resistance to social distancing and masks. At the same time, nations are plagued by shortages and distrust of the flu vaccine.

“There’s a considerable concern, as we enter the fall and winter months and into the flu season, that we’ll have that dreaded overlap of two respiratory-borne diseases,” warns Anthony Fauci, M.D., director of the U.S. National Institute of Allergy and Infectious Diseases.

Covid-19 and influenza share many symptoms: fever, cough, muscle aches, fatigue, sore throat, and headache. As a result, symptom onset may send a flood of people to emergency rooms, unsure which disease they may have.

Some may even have both, a particularly worrying scenario. Hospitalized adults who contract both diseases face 2.3 times the risk of death compared to those with Covid-19 alone, according to Public Health England. What’s more, influenza infection appears to leave patients vulnerable to a more serious bout of Covid-19.

Both influenza and SARS-CoV-2 can spread via aerosol and before symptoms appear. These two facts point to a single imperative for hospitals and nursing homes: continual air dis-infection.

Air-management strategies are “important protections against spread of infection within healthcare settings,” asserts Australian virologist Ian Mackay, PhD, an expert in influenza transmission.

The same strategies, including air dis-infection with low-energy plasma technology, can be deployed in schools, pharmacies, offices, and restaurants — any indoor space where infectious pathogens are sure to be hovering.

When operated 24/7, air dis-infection units can reduce the transmission odds of both SARS-CoV-2 and influenza. Whether installed on a wall or a shelf, these devices operate safely, unobtrusively, and — of particular importance — without reliance on human effort.

As the population’s energy and patience wanes, low-energy plasma technology has become a critical line of defence against two viruses certain to wreak havoc this winter.

“Frightening” Indifference to the Flu Vaccine

While the world awaits a coronavirus vaccine, we already possess an effective flu shot, —considered a powerful weapon against the feared twindemic. Widespread influenza vaccination, Dr Fauci emphasizes, can “help eliminate at least eliminate at least one” of the two diseases, and the vaccine significantly reduces the severity of symptoms of those who become infected.

Yet vaccination rates are dismal.

Even in the United States, where the flu vaccine is available to everyone and heavily promoted at supermarkets, distrust and disinterest are pervasive. In the flu season that ended just as Covid exploded, just 45% of U.S. adults were vaccinated.

Scepticism abounds: 34% of American adults don’t think flu vaccines work well, and 29% fear side effects. This winter, 17% plan to forego the vaccine for fear of contracting Covid-19 by venturing out.

Vaccination rates are far lower in Europe, where the flu shot is recommended only for high-risk groups, such as the elderly, healthcare workers, and those with chronic health conditions.

Among Europeans ages 65 and older, just 44% are vaccinated, a far cry from the World Health Organization’s target of 75% and far lower than the 60% of American seniors who get vaccinated. Half the countries in the European WHO region vaccinate fewer than 1 in 3 older people, even though flu vaccination reduces the risk of flu-related hospitalization among seniors by 61%.

Just 30% of European healthcare workers get vaccinated annually; in Italy, the rate is just 15%. These paltry figures include healthcare workers at nursing homes, locations highly vulnerable to both influenza and Covid-19 outbreaks.

“Vaccination coverage among high-risk groups has unfortunately been declining in a number of countries in the Region in recent years,” reports the WHO.

Even this year, only half of eligible Germans plan to get vaccinated, a scenario the country’s pharmacists consider “frightening.”

To be sure, the Covid explosion has been a wake-up call for some; globally, the twindemic threat has spiked demand for the flu vaccine. However, distribution and supply problems abound.

Though the United States is well stocked with vaccine, many of the offices, schools, and manufacturing plants that offered free shots on site are closed because of the pandemic.

Europe has bigger problems. Having placed vaccine orders prior to the explosion of Covid-19, most EU countries don’t have enough vaccine to meet demand.

In Belgium, which faces a “tsunami” of Covid cases, offering flu vaccinations to those who fall outside the highest-risk groups is “out of the question,” according to the country’s pharmacists. In Britain, pharmacies have stopped offering flu shots; only 25% of general practitioners expect to have enough flu vaccine to last the winter.

Hospital Flu Outbreaks: “Underdetected and Underreported”

Of course, even if flu shots were universally available and welcomed, the vaccine is not a panacea. Influenza mutates frequently, and some flu strains are especially apt to replicate in the body. The vaccine’s effectiveness in a given year ranges from 40% to 60% and is lower for seniors.

As well, immunity wanes over time; those vaccinated early in the season are less protected at the end.

For plenty of reasons, then, influenza takes a large toll each winter and into early spring. In the United States, about 8% of the population develops a symptomatic infection. In Europe, annual infection rates range between 5% and 15%.

In the coronavirus era, the severity of influenza gets downplayed. Certainly, the flu is far less lethal than Covid-19, but many of the vulnerable suffer severe complications: pneumonia, heart attacks, myocarditis, and strokes.

In the United States, some 740,000 people were hospitalized with the flu during 2019/2020, a mild flu season, and up to 62,000 Americans died from the disease. In the WHO European Region each year, about 44,000 deaths are associated with seasonal flu.

Even without the added threat of Covid-19, a high caseload of even mild to moderate influenza overtaxes medical services and compromises productivity in the workforce. In some years, hospital units are forced to close temporarily because so many healthcare workers become infected.

“Any patient, healthcare worker or visitor is capable of transmitting [influenza] to susceptible persons within hospitals,” French scientists wrote in a review paper of hospital-acquired flu outbreaks. The French team noted that such outbreaks are “probably under detected and underreported.”

Nursing homes, too, are hot spots for influenza outbreaks. The close living quarters and fragile health of residents make these facilities “conducive to the rapid spread of influenza virus.”

Flu outbreaks not only have “devastating consequences for individuals,” the authors wrote, but also place substantial strain on health services. During the flu outbreaks studied, 33% of residents become infected, and 6.5% died. Though staff were considerably younger and healthier, 23% contracted the flu.

Read part two here.

Clean Hospitals Day – 10/10/20

Novaerus is delighted to be supporting Clean Hospitals Day, a global awareness campaign created to highlight the importance of healthcare environmental hygiene.

On the 10th of October 2020, Clean Hospitals Day will celebrate and empower key environmental hygiene healthcare workers. This day also represents a call to hospital management, decision-makers and stakeholders to champion environmental hygiene and to take action to make hospitals cleaner and safer.

Clean Hospitals Day aims to ensure recognition of the importance of healthcare environmental hygiene, to provide stronger focus and guidance and to define and share a global understanding for hygiene standards. The global campaign will address all the components of healthcare environmental hygiene such as surfaces, air, medical waste, fabrics and fittings, water, IT, digitalization and much more.

To learn more about Clean Hospitals Day, visit the website.

Please join us on 10/10/20 and let’s celebrate Clean Hospitals Day together – #CleanHospitalsDay.

As part of the campaign, Clean Hospitals are holding a  free teleclass – Clean Hospitals: The Next Frontier in Infection Prevention on the 20th of October at 7.30 PM CEST.  The teleclass will be taught by Prof Didier Pittet, Chair of Clean Hospitals, and Dr Pierre Parneix, Education Director of Clean Hospitals, who will address pressing questions in healthcare environmental hygiene, explaining why it is key for preventing healthcare-associated infections and protecting staff and our environment. 

Register for the free teleclass here. 

In preparation for the teleclass, from the 10th – 20th of October, Clean Hospitals will release 10 mini videos with questions about healthcare environmental hygiene. These questions will be answered during the teleclass. 

Follow Clean Hospitals on social media to make sure you don’t miss out!

Clean Hospitals is a coalition of international stakeholders who work explicitly to promote Healthcare Hygiene. Clean Hospital’s vision is to be the guardians protecting healthcare workers, patients and the environment, believing that by making care facilities a cleaner place, the healthcare system will be better equipped to protect its inhabitants.

Infection Spread in the NICU: “The Tip of the Iceberg” – Part 2

COVID-19 aside, respiratory viral infections (RVIs) strike newborns particularly hard and, according to Austrian researchers, are “more prevalent in the NICU than previously considered.” RVIs are likely underdiagnosed, the authors assert, as many NICUs don’t routinely test for viral pathogens in symptomatic patients. Respiratory viral infections are a leading cause of mortality among newborns and often are detected only late in the course of illness.

Read part one of this blog post here.

Viral Outbreaks in the NICU

Though the majority of NICU infections are bacterial, nosocomial viral infections have been widely reported, including outbreaks of syncytial virus (RSV), influenza H1N1, rotavirus, adenovirus, enterovirus, and norovirus.

COVID-19 aside, respiratory viral infections (RVIs) strike newborns particularly hard and, according to Austrian researchers, are “more prevalent in the NICU than previously considered.”

RVIs are likely underdiagnosed, the authors assert, as many NICUs don’t routinely test for viral pathogens in symptomatic patients. Respiratory viral infections are a leading cause of mortality among newborns and often are detected only late in the course of illness.

The hospital costs of RVIs are particularly high. A 6-year study of a NICU in Nottingham, UK, found that compared to uninfected newborns, infected NICU patients spent far longer in the hospital — 76 days compared to 41 days — and in-hospital care costs were significantly higher, £49,664 compared to £22,155.

Infected NICU staff are often the source of viral outbreaks, especially influenza infection.

Newborns, of course, cannot be vaccinated, and annual vaccination rates among the healthcare workers who care for these patients are alarmingly low.

An H1N1 influenza outbreak in a Greek NICU, for example, was traced to the nursing staff, just 15% of whom were vaccinated.

“Nosocomial influenza can cause considerable morbidity, especially in high-risk neonates,” the authors wrote, “and is readily transmissible in the NICU setting by unvaccinated staff members.”

Viral infection spreads quickly in the NICU. A norovirus outbreak at Texas Children’s Hospital, traced to one newborn, began spreading within 24 hours and within two weeks had afflicted 28 babies, along with 12 staff members, who had to be furloughed.

Disinfecting the NICU Air, Safely and Quietly

Hand hygiene has long been the cornerstone of hospital infection prevention, in the NICU and elsewhere, and healthcare workers are striving to be even more meticulous in the COVID era. Yet hundreds of studies demonstrate that over the decades, compliance has been, in the words of the World Health Organization, “abysmally low.”

Surface cleaning, too, has been augmented since the emergence of SARS-CoV-2 but inevitably falls short, as airborne pathogens continually settle on medical equipment, floors, clothing, and healthcare workers’ hands.

It is impossible to operate [NICU] environments in complete sterility,” a University of California team reported. The infants themselves, the adults who care for them, the equipment required for their care — all represent “fertile vectors for microbial transmission.”

Though stringent cleaning protocols for NICU surfaces have been in place for years, infections rates remain stubbornly high.

“It is tempting to speculate that more potent cleaning techniques or agents will lead to further decreases in nosocomial infections,” the researchers concluded, but reality may be otherwise. “Future improvement may require innovative approaches.”

Among the most effective innovations is ultra-low-energy plasma technology by Novaerus, now deployed in NICUs and COVID wards worldwide. Easily installed on the wall, a shelf, or a rolling stand, Novaerus devices quickly destroy airborne viral, bacterial, and fungal particles.

For example, lab tests found the company’s most powerful unit can reduce the airborne load of MS2 Bacteriophage, a virus used as a surrogate for SARS-CoV-2, by 99.99% in just 15 minutes. The technology decimates MRSA load just as thoroughly and quickly.

Dis-infecting air in the NICU, as well as other wards and common areas, is imperative, as study after study points to hospital infection spread via aerosolization. A Japanese team, for example, reported on an outbreak of Bacillus cereus in its NICU, concluding the bacteria spread via the airflow of the ventilation system. Numerous studies have detected MRSA and Clostridicum difficile in hospital air.

As for SARS-CoV-2, air-sampling studies have detected viral RNA in hospital hallways and in rooms where healthcare workers changed their clothing, prompting the World Health Organization to finally agree with scientists worldwide that aerosol transmission of COVID-19 cannot be ruled out.

In a year-long study of an American NICU, a team of environmental engineers noted in PLOS One: “Hospital hygiene protocols may undervalue the potential importance of the airborne transmission route.”

Throughout hospitals, but especially in the NICU, ultra-low-energy plasma technology is an important addition to ventilation and filtration. Whereas conventional filters capture only large particles, Novaerus units destroy the smaller and deadlier ones.

Novaerus units run continuously and quietly, a benefit given the adverse effect of noise on the heart rates and respiratory systems of preterm or very low birth weight infants.

The technology is safe to operate around even the smallest, most medically fragile NICU patients, unlike other air-sanitation methods that can produce harmful byproducts.

Novaerus technology not only helps prevent infection but also mitigates newborns’ exposure to chemicals such as volatile organic compounds (VOCs) and particulate matter. Lacking the protective buffer of the womb, research suggests, newborns in the NICU are exposed to chemicals that may permanently alter neurobehavioral outcomes.

Air quality in the NICU may have a “significant impact on their long-term development,” note researchers at the Icahn School of Medicine at Mount Sinai in New York City, who are conducting the first study of air quality in neonatal intensive care.

Infants admitted to the NICU often stay for long periods, putting them at elevated risk for contracting an infection. The average length of stay for a term or near-term infant with surgical or respiratory issues is about 15 days; the length of stay for preterm infants born at 26 weeks’ gestation is more than 2 months.

Throughout their stay, it is imperative that their infection risk is reduced by stringent hand hygiene, effective surface cleaning, and 24/7 air dis-infection.

Microbes accumulate 24 hours a day, as visitors, staff, and medical devices come and go. Healthcare workers’ hands and NICU equipment cannot be cleaned continually, but with the installation of Novaerus technology, the air in the NICU can.

Infection Spread in the NICU: “The Tip of the Iceberg” – Part 1

Late one summer at the Children’s Hospital of Philadelphia, a top American medical centre, routine microbiological surveillance revealed something unusual in the neonatal intensive care unit: Over four weeks, 23 newborns tested positive for adenovirus, though not a single NICU patient had been infected with the virus the entire previous year.

The outbreak was cause for alarm.

In healthy children, adenovirus particles — launched airborne by coughs and sneezes and hardy enough to survive for weeks on surfaces — cause little more than a sore throat or pink eye. But in ill newborns, the most fragile of patients, adenovirus can trigger dire respiratory complications. Indeed, among the infected babies in Philadelphia, 12 required extra breathing support and 5 developed pneumonia. Four babies died.

An intense investigation traced the outbreak to contaminated eye-exam instruments — lenses and scopes that, notably, had been touched only by providers. In other words, the investigators emphasized, adenovirus can be spread even by equipment “that does not directly contact patients.”

These days, concern about infection spread at hospitals largely revolves around Covid-19. But well before the emergence of SARS-CoV-2, containing dangerous pathogens was an urgent and complex battle for hospitals, particularly in the NICU.

The coronavirus pandemic has only increased the risks facing the smallest, most vulnerable patients. To protect hospitalized newborns and assuage their anxious parents, hospitals are bolstering their infection-control strategies, minimizing the number of healthcare staff and visitors allowed near NICU patients, augmenting hand-hygiene protocols, and deploying air dis-infection technology to eradicate pathogens in the NICU air.

“This is an exceptional time,” says Hany Aly, M.D, chair of neonatology at Cleveland Clinic, a prominent American hospital that has made numerous changes to its infection-control practices.

Airborne Pathogens: Nothing New in the NICU

Indeed, today’s circumstances are exceptional, but in reality, augmented infection-control practices in the NICU were warranted prior to the pandemic and will remain so when the Covid-19 crisis abates.

In developed countries worldwide, up to 25% or 30% of NICU patients may contract an infection, whether viral, bacterial, or fungal. Developing countries bear a much higher burden.

NICUs account for 18% of all hospital infection outbreaks recorded in the worldwide Outbreak Database, numbers that may represent “only the tip of the iceberg,” according to Jayashree Ramasethu, M.D., NICU director at MedStar Georgetown University Hospital in the United States.

Premature and ill infants are, of course, highly susceptible to infection, because of their immature immune systems and fragile skin and because the very devices they depend on for life, such as ventilators and catheters, are common channels for bacterial invasion.

What’s more, advances in neonatal care are increasing the NICU’s population of smaller and sicker infants, the patients most likely to develop and succumb to serious infection.

As Dr Ramasethu notes, infection spread in the NICU presents hospitals with a daunting trifecta: “serious consequences for patients, huge economic burdens and staffing issues.”

The average NICU infection outbreak strikes 24 patients, with a mortality rate of 6.4%, according to a German review of 276 NICU outbreaks. As for the financial burden, infections often add weeks to a newborn’s hospital stay while more than doubling the cost, as British research has shown.

Superbug Outbreaks in the NICU

Thus far, only a small number of infants have contracted Covid-19, primarily from their caregivers, and no cases of in-hospital transmission have been reported. Most infants who have contracted the disease have recovered without complication, though severe cases requiring mechanical ventilation have been reported, and clearly, the utmost precautions must be taken around infected babies.

Compared to adults, “neonates tend to have a milder infection based on the very limited number of cases published so far,” according to a peer-reviewed literature review.

However, the same cannot be said for the way newborns fare when infected by pathogens other than SARS-CoV-2. Among the dangerous microbes known to lurk in the NICU, the superbug MRSA may be the most concerning.

“Neonates are particularly vulnerable to colonization and infection with MRSA,” cautioned a research team at Yale University School of Medicine in the United States.

About 30% of MRSA-colonized babies will develop an invasive infection. Among the potentially dire consequences: sepsis, meningitis, necrotizing pneumonia, respiratory tract infection, and endocarditis.

MRSA outbreaks in NICUs have been reported worldwide — in Germany, Great Britain, Israel, Japan, Scotland, Taiwan, and elsewhere — and incidence of MRSA in the NICU is skyrocketing.

The Yale study, reviewing data from 149 NICUs, found MRSA infections increased by 308% over a decade. The emergence of multi-drug resistant MRSA strains, the authors warned, suggests “difficulties treating MRSA infections will only continue to escalate.”

Another study found MRSA infection in the NICU independently increased the newborns’ length of stay by 40 days and added, on average, over $164,000 in costs per patient.

MRSA droplets can hover in the air and can survive for weeks on floors, door handles, sinks, mops, nursing scrubs, and towels, allowing for easy transmission to newborns.

The bacteria is so easily spread that when a triplet, later discovered to have been colonized, was transferred from one Danish NICU to another, 32 newborns in the second NICU became colonized with the same rare MRSA strain. The index patient had become colonized during a 15-day stay in a room adjacent to an isolation room that had housed an MRSA-infected newborn.

Read part two here

When Life-Saving Procedures Emit Deadly Aerosols: How Hospitals Can Protect Front-line Workers

Well before SARS-CoV-2 began rampaging the globe, two virologists — one Dutch, one American — worried that just such a virus would explode and strike healthcare workers particularly hard.

The scientists, Vincent Munster, Ph.D., and Seth Judson, Ph.D., knew that the MERS and SARS coronaviruses had infected medical workers at alarmingly high rates. And they knew one reason why: many of these providers had performed or been present for, life-saving procedures that generated virus-laden aerosols.

Some healthcare workers had administered chest compressions. Others had performed bronchoscopies or tracheal intubations, airway-irritating procedures that can trigger forceful coughs and, in the process, release highly infectious aerosol clouds.

In a prescient paper, published two months before SARS-CoV-2 surfaced in China, Munster and Judson warned that emerging viruses, having jumped from animals to humans, would likely threaten the lives of doctors and nurses on the front lines.

“The viruses that pose the highest risk to healthcare workers performing aerosol-generating procedures may be some of the viruses that we know the least about,” they cautioned.

Of course, now we know about SARS-CoV-2.

Now more than 90,000 healthcare workers have been infected by the virus worldwide, and at least 1,000 have died.

Every day, nurses and doctors caring for Covid-19 patients perform the very procedures linked to provider infections during the outbreaks of Severe Acute Respiratory Syndrome (SARS) in 2002 and Middle Eastern Respiratory Syndrome (MERS) in 2012.

“During these procedures, viral particles can remain suspended in the air with a half-life of approximately 1 hour and be inhaled by those nearby,” a team of critical-care physicians cautioned in Circulation.

As the team noted, procedures such as CPR and tracheal intubation are often performed in tense, high-stress situations, as patients go into shock or cardiac arrest, their oxygen levels plummeting. Sufficient personal protective gear may not be at hand. Lapses in infection-control practices happen.

In these trying circumstances, healthcare workers need extra protection from infectious aerosols. Hospitals must look beyond face shields and respirators and consider the larger critical-care environment, ensuring appropriate room ventilation and outfitting ICUs and ERs with air dis-infection technology.

Aerosols Aloft: “Healthcare staff are extremely stressed”

When tuberculosis patients can’t cough up secretions on their own, they’re given a nebulized saline solution to inhale. This procedure, sputum induction, promotes coughing and can generate infectious aerosols. So can bronchoscopy, also performed often on TB patients.

Some years ago, the emergence of drug-resistant tuberculosis — now a serious global health threat — spurred concern about the potential risks of aerosol-generating procedures such as these. But it was the SARS outbreak that sounded a louder alarm.

During the eight-month, 29-country outbreak, infection rates among healthcare workers were astonishing: among SARS patients overall, 21% were healthcare workers. In Singapore, medical workers accounted for 40.8% of cases and in Toronto, 51%.

Initially, scientists assumed the SARS coronavirus was spread only via large droplets and close contact, the same assumption initially applied to SARS-CoV-2. But researchers later found cases in which droplet transmission simply “could not have been feasible.”

In one instance, chest compressions and tracheal intubation were performed on a SARS patient in respiratory failure. Three days later, one of the nine healthcare workers present tested positive for the virus — even though she’d worn two pairs of gloves, two gowns, safety glasses, a face shield, shoe covers, a hair cover, and an N95 respirator.

What’s more, she had not been involved in the CPR or intubation; her job was to insert an IV catheter into the patient’s left foot.

Had the nurse inhaled aerosols generated by those procedures? It’s impossible to know. And it would be near-impossible to capture air samples while providers converge around a desperately ill patient. (Air samples isolated during sputum induction of TB patients have proven to contain viable TB aerosols.)

Still, retrospective SARS studies make a compelling case.

For example, a Canadian team analyzed the treatment of 7 hospitalized SARS patients and the infection rate among the 122 healthcare workers who cared for them.

Compared to staff never involved in tracheal intubation, those present just prior to and during intubations were at “substantially increased risk” of contracting SARS.

Studies like these have alarmed today’s critical-care workers.

“Healthcare staff are extremely stressed about managing Covid-19 patients,” says Jerry Nolan, M.D., a CPR expert and chair of the European Resuscitation Council.

The high rate of Covid-19 infection throughout the pandemic has only compounded the stress. In Spain, healthcare workers account for nearly 14% of Covid-19 patients, and in Italy, about 10%.

Which Procedures Generate Aerosols?

There’s no definitive list of aerosol-generating procedures and a fair amount of controversy on the topic. For example, over the years, the World Health Organization (WHO) has listed, de-listed, and then re-listed CPR as an aerosol-generating procedure.

At the moment, says Dr Nolan, “a consensus is evolving that chest compressions are highly likely to be generating, at the very least, droplets and probably airborne particles.”

Performing CPR on Covid-19 patients appears to be so risky that experts have issued unprecedented guidelines for providers.

Typically, doctors and nurses spring into action to perform chest compressions; now, they’re being advised to “take a pause” and consider whether there may be a less perilous alternative.

CPR and endotracheal intubation are considered by most health organizations to generate aerosols. In addition, the World Health Organization (WHO) lists bronchoscopy, open suctioning, manual ventilation before intubation, turning a patient to the prone position, and disconnecting a patient from a ventilator.

The U.S. Centers for Disease Control and Prevention (CDC)’s list is less definitive. However, the CDC considers endotracheal intubation to be “especially hazardous,” as high viral loads of SARS-CoV-2 are found in sputum and upper respiratory secretions of patients with Covid-19.

Drs. Munster and Judson divide aerosol-generating procedures into two categories: 1.) those that mechanically create and disperse aerosols, such as CPR, intubation, and bronchoscopy, and 2.) those that induce the patient to produce aerosols, such as ventilation, suctioning, and nebulization.

Protect Medical Workers with Air Dis-infection Technology

It may take years for scientists to agree on which procedures generate aerosols, but front-line medical workers don’t have the luxury of time. They have patients in cardiac arrest and respiratory distress, and they need immediate protection from any SARS-CoV-2 particles wafting about.

So, healthcare workers are innovating. At some hospitals, they’re performing endotracheal intubations through clear plastic drapes outfitted with armholes or through a plexiglass box, known as an aerosol blocking shield, that fits over the patient’s head.

Still, these devices haven’t been well studied and may limit the anesthesiologist’s view and/or range of motion. Also, they’re designed for intubation and won’t help with the half-dozen other procedures likely to generate aerosols.

Certainly, all hospitals are trying to limit scenarios that would prolong aerosol exposure, such as failed intubation attempts, by assigning their most experienced clinicians. But this pandemic is an all-hands-on-deck situation. The best person for the job may not always be available.

Of course, for any procedure, the most critical protection is personal protective equipment (PPE). Both WHO and CDC recommend healthcare workers present for aerosol-generating procedures wear an N95 or higher-level respirator, eye protection, gloves, and a gown.

But PPE shortages have been dire worldwide, and in emergency settings, even a complete ensemble may not offer full protection. The Toronto nurse who contracted SARS despite wearing extensive PPE was not an isolated case.

Lab studies confirm the limits of PPE. For example, an Israeli team simulated endotracheal intubation using a fluorescent marker to visualize exhaled respiratory particles. They found fluorescent markers on the uncovered facial skin, hair, and shoes of personnel “performing” the intubations, even though all wore required PPE. It’s well known that viral particles on clothing can be re-launched airborne.

The upshot: PPE “may not fully prevent exposure” to aerosols generating during emergency endotracheal intubation.

Given the limits of these and other common precautions, hospitals are recognizing they must protect workers by optimizing the larger critical-care environment.

Ideally, all aerosol-generating procedures would be performed in negative-pressure isolation rooms; the ventilation system allows air to flow into, but not escape from, the infected patient’s room.

But in the United States, for example, only 2% to 4% of all hospital rooms are equipped for negative pressure, and hospitals hard hit by Covid-19 may not have the resources to quickly convert other spaces.

What’s more, even rooms designed for negative pressure may not do the job. In a study that analyzed over 600 of these rooms, just 32% met ventilation standards.

It’s important, then, for hospitals to provide workers with an additional layer of protection: ultra-low-energy plasma technology by Novaerus.

Commonly installed in ICUs and emergency departments, Novaerus air dis-infection devices operate continuously and are safe around the most vulnerable patients, including Covid-19 patients in respiratory or cardiac distress.

Novaerus technology kills 99.99% of MS2 Bacteriophage, a surrogate for SARS-CoV-2, in 15 minutes, laboratory testing shows.

The protection extends far beyond Covid-19 and other coronaviruses. Novaerus technology kills other highly contagious viruses, such as influenza, norovirus, and measles, as well as dangerous bacteria and fungi that plague hospitals, such as MRSA, Clostridium difficile, and Aspergillus niger.

In an interview for the This Week in Virology podcast, conducted two years before SARS-CoV-2 was unleashed upon the globe, Vincent Munster of the U.S. NIH, an expert on MERS-coronavirus, was interviewed about the pandemic potential of coronaviruses.

“As virologists, we always kind of work from a worst-case scenario,” he told the interviewer.

SARS-CoV-2 has become that worst-case scenario.

The virus has overwhelmed the world’s healthcare systems, infecting more than 5 million people and killing more than 350,000 — and counting.

To prevent the pandemic from inflicting even more damage, on healthcare workers and patients alike, hospitals must deploy all available weapons, including air dis-infection technology.

Covid-19 and PM 2.5: The Stakes Have Risen for Hospital Building Health

Vanishing air pollution has been a big Covid-19 story, told in dramatic before-and-after images: Skyscrapers once obscured by a yellowish haze suddenly appear in sharp focus, now that factories have closed and traffic is sparse.

But as nations emerge from lockdown and cities roar back to life, that toxic haze will reappear — and, as before, will seep into our medical centres, posing risks to patients and healthcare workers alike.

Except this time, with a new pathogen in our midst, the stakes for hospitals will be higher.

For the foreseeable future, healthcare facilities will be contending with Covid-19, a disease with strong and documented links to polluted air.

Two robust studies, one American and one Italian, have found that Covid-19 patients with more exposure to particulate matter face a higher risk of dying. The researchers focused on PM2.5, toxic particles small enough to penetrate lung tissue.

“If you’re breathing polluted air and your lungs are inflamed by the disease, you’re going to get very, very sick,” cautioned biostatistician Francesca Dominici, Ph.D., a Harvard University Harvard biostatistician and co-author of the American study.

Dr Dominici was referring to long-term PM2.5 exposure, as measured outdoors. However, other research has linked even daily spikes in particulate matter to surges in heart attacks and asthma attacks; still, other studies demonstrate that hospitals are not sealed off from the airborne toxins outside.

“Indoor concentrations of many pollutants can be higher than outdoors,” notes Joseph Allen, DSc, director of Harvard University’s Healthy Buildings Program and a forensic investigator in hospital disease outbreaks.

As a group, hospital patients are highly vulnerable to the health risks of air pollutants. Covid-19 patients, many of them intubated or ventilated, may be the most vulnerable among the vulnerable.

As these patients struggle to survive, what they need least is further exposure to airborne pollutants.

Though lockdowns will ease, the novel coronavirus will persist for some time, as that polluted haze reappears. It’s a worrisome scenario — and one hospitals must prepare for by eradicating indoor particulate matter, especially in wards where Covid-19 patients are treated.

Covid-19 and Pollution Exposure

Air pollution has long been linked to respiratory infection and disease. Just as PM2.5 damages nature, turning streams acidic and depleting soil nutrients, these toxic particles inflame human tissue and deplete immunity.

So when a respiratory virus strikes, those with pollution-impaired lungs and weakened defences are primed to suffer the most.

This proved true when the SARS coronavirus surfaced in 2002.

Patients from highly polluted regions in China were twice as likely to die as those who’d breathed relatively clean air in the previous two months, as well as the previous two years. Even SARS patients from moderately polluted regions in China were 84% more likely to die than those exposed to low pollution levels.

So, the study results on SARS-CoV-2, its wilier cousin, are unsurprising.

“We know fine particulate matter affects the respiratory system. And we know that Covid-19 kills by affecting the respiratory system. So we know, by science, that getting [the disease] is like adding gasoline to the fire,” says Harvard’s Dr. Dominici, co-author of the American study.

In her study, patients from heavily polluted counties in the United States were 15% more likely to die from Covid-19 than patients in counties with cleaner air.

Just a small increase in PM2.5 exposure corresponded with a large increase in the Covid-19 death rate. The impact of PM2.5 exposure on death from Covid-19 was 20 times greater than the impact of pollution exposure on death from all causes.

The Italian results were even starker.

Northern Italy is among Europe’s most polluted regions, due largely to an unlucky combination of climate and geography: wind is rare, and climatic inversions aren’t. Among patients in the region stricken with Covid-19, the death rate over a one-month period was an astonishing 12%, compared to 4.5% elsewhere in Italy.

“It is well known that pollution impairs the first line of defence of upper airways,” wrote the authors, in Environmental Pollution. It only follows, they observed, that residents who inhale more pollutants would be more vulnerable to respiratory infection.

For the vulnerable, it doesn’t take a lifetime of pollution exposure to trigger a poor health outcome; a few days of inhaling highly toxic air may do the job.

Diabetes, COPD, Parkinson’s disease, asthma, tissue infections, kidney failure — hospitalizations for all these conditions surge on days when air pollution spike.

What’s more, it doesn’t take exceedingly high levels of pollution to wreak havoc on the health of a vulnerable person.

In an American study, the link between exposure to fine particulate matter and hospitalizations held even when the daily air pollution levels were lower than current World Health Organization standards.

The health dangers of air pollution are “significantly larger than previously understood,” warned biostatistician Yaguang Wei, Ph.D., the study’s lead author.

Likewise, Australian researchers, using data from Japan, found that for older patients, even brief exposure to relatively low levels of particulate matter can increase risk of cardiac arrest. In their study, over 90% of the heart attacks occurred when pollution levels were below WHO standards.

“There is no safe level of air pollution,” cautioned study co-author, Kazuaki Negishi, M.D., a cardiologist University of Sydney School of Medicine.

Cleaner Hospital Air: Safer for Patients and Healthcare Workers Alike

Air pollution inside hospitals was a concern long before the novel coronavirus jumped from animals to humans.

We know this microscopic mixture of dust, soot, and chemical particles can travel hundreds of miles and can waft indoors via doors and windows. Other airborne toxins, such as volatile organic compounds (VOCs), originate inside buildings, emitted by building materials, cleaning supplies, even shampoos and lotions.

Particulate matter, like dangerous bacteria and viral particles, also can hitch a ride on clothing, only to be launched airborne when a lab coat or gown is removed.

Even among healthy people, PM2.5 can irritate the eyes and lungs, trigger headaches, exacerbate allergies, and impair memory and the ability to do simple math.

By contrast, studies show, breathing clean air on the job makes you feel better and think more clearly, especially in a crisis.

A few years back, Harvard’s Joseph Allen sent architects, managers, and other professionals to work amidst varying levels of airborne pollutants. He then challenged them with a series of simulated scenarios, such as taking charge in a crisis as an emergency coordinator.

The subjects had to plan, prioritize, and sift through loads of information under high-stress conditions.

“We found that breathing better air led to significantly better decision-making,” Dr Allen reported.

For hospitals, of course, crises occur daily, decisions are matters of life and death, and these pollution-sensitive skills are essential, more so than for the typical manager.

Dr Allen suspects the coronavirus pandemic will turn clean indoor air into an important commodity, one that business leaders and landlords will leverage “as recruitment tools and sources of competitive advantage.”

Hospitals, of course, have different priorities. Recruitment and competition take a back seat to saving lives and protecting healthcare workers.

Given these high stakes, hospitals must go well beyond measures used by business leaders, deploying medical-grade technology to eradicate the pollutants floating about their facilities.

Unlike SARS, Covid-19 will not vanish any time soon. A vaccine is far off, and more distant still is the day when vaccine rates are high enough to vanquish the disease.

As the WHO has warned, “the worst is yet ahead of us.”

Eyeing this future, Dr Allen advises an all-out attack on Covid-19: “That means unleashing the secret weapon in our arsenal — our buildings.”

By deploying a single air dis-infection technology, hospitals can achieve multiple goals: mitigating the spread of SARS-CoV-2 and eradicating the airborne toxins that may compromise the recovery of patients and the quick thinking of doctors and nurses.

Ultra-low energy plasma units by Novaerus not only kill  99.99% of MS2 Bacteriophage, a surrogate for SARS-CoV-2 (COVID-19), in 15 minutes according to laboratory studies but also remove 99% of PM2.5 inside a chamber in 6.26 minutes.

These portable units operate 24/7 and are safe for continuous use around the most vulnerable patients.

For these reasons, hospitals worldwide are installing Novaerus units in ICUs and Covid-19 wards.

It’s clear that cleaner hospital air may benefit not just coronavirus patients but also the staff who care for them.

Silent Spreaders: What Asymptomatic Transmission of Covid-19 Means for Hospitals

When Adriano Trevisan died of COVID-19 in early 2020, he became the disease’s first Italian fatality. His death, at age 77, spurred a chain of events that have shed light on a critical question: How often is the disease spread by people without symptoms?

Trevisan lived in a hillside village near Venice. Upon his death, the local governor not only quarantined the entire village but also ordered all 3,341 residents to be tested for SARS-CoV-2 twice, before the lockdown and two weeks later.

What the testers found: Among the 88 villagers infected, at least 50% were “completely asymptomatic,” reported Sergio Romagnani, M.D., a professor of clinical immunology at the University of Florence, who was involved in the testing.

Romagnani called asymptomatic transmission “a formidable source of contagion.”

How formidable?

That remains to be seen, but the Italian results, though unpublished and on the high side, generally align with COVID-19 studies of cruise-ship passengers, Icelandic volunteers, and hospitalized patients in Tibet.

The U.S. Centers for Disease Control and Prevention’s director, Robert Redfield, M.D., estimates the number of “covert cases” at 25%.

“This helps explain how rapidly this virus continues to spread,” Dr Redfield said.

The World Health Organization (WHO) maintains that most patients classified as asymptomatic are actually pre-symptomatic — people who felt fine when tested but later developed the telltale fever, cough, and aches. WHO has called the percentage of truly asymptomatic cases “relatively rare.”

Nonetheless, WHO agrees with the scientific consensus that asymptomatic transmission is not rare.

Whether asymptomatic people never fall ill or whether they go on to develop symptoms, the fact remains: infected people transmit SARS-CoV-2, the virus causing COVID-19, while feeling perfectly healthy.

“The bottom line is that there are people out there shedding the virus who don’t know that they’re infected,” said Jeffrey Shaman, Ph.D., a public health expert at Columbia University in New York City.

Silent spreaders, covert cases, submerged infections, stealth transmission — whatever term you use, the phenomenon poses no small challenge for controlling the spread of COVID-19, especially at healthcare facilities.

In the novel coronavirus, hospitals face a daunting combination of circumstances: a deadly disease that is likely transmitted through the air and spread by people who may never even get sick.

As evidence mounts that SARS-CoV-2 can be spread via aerosol, hospitals must respond by taking extra measures to prevent stealth transmission among healthcare workers.

How Common Are Covert Cases of COVID-19?

Submerged infection is nothing new. Norovirus, influenza, human respiratory virus, mild coronavirus strains — every day, millions walk around oblivious to the fact that they’re infected with one virus or another.

A few years back, before SARS-CoV-2 was unleashed upon humans, researchers stood at a New York City tourist attraction and swabbed 2,600 visitors who volunteered to be tested. Among the tourists, 6.2% tested positive for a virus; 65% to 97% of the infections were classified as asymptomatic.

Among people infected with measles, 8% may never develop symptoms; with norovirus, about 32% don’t fall ill.

As scientists work to determine where COVID-19 fits in, the most useful data comes from closed-off populations who’ve undergone comprehensive testing.

Adriano Trevisan’s Italian village was one such population; the Diamond Princess cruise ship was another. Quarantined for two weeks off the port of Yokohama, Japan, the Diamond Princess had over 3,700 passengers and crew aboard.

Two days after the ship docked, 21% of the passengers tested positive for COVID-19; among those infected, 17.9% never developed symptoms.

“The substantial asymptomatic proportion for COVID-19 is quite alarming,” said American epidemiologist Gerardo Chowell, Ph.D., part of the research team.

Chowell notes that most of the ship’s passengers were over 60 and therefore at elevated risk for developing symptoms; among the general population, he estimates, the proportion of covert cases may be as high as 40%.

In Iceland, about 50% of volunteers who tested positive for COVID-19 reported feeling no symptoms, though the sample of 9,000 was entirely self-selected, and it’s likely some of them were pre-symptomatic.

More compelling was an analysis of COVID-19 patients quarantined in a hospital in Tibet.

In this study, there were no doubts: All local residents who tested positive — 83 patients — were hospitalized for two weeks and thoroughly examined. Among them, 21.7% neither demonstrated nor reported symptoms during the surveillance period.

These patients weren’t feverish or coughing or achy, yet most had “viral pneumonia-like changes” in their medical workups. Some 83% had abnormal blood chemistry, and 39% had abnormal chest CT images.

How Contagious Are People Without Symptoms? 

Clearly, plenty of people infected with the novel coronavirus are walking around without fevers or coughs. But are they contagious?

Certainly, covert carriers of other viral diseases can transmit infection.

“For measles and norovirus infections, it is well established that asymptomatic individuals are frequently able to transmit the virus to others,” wrote the Diamond Princess research team.

Typically, it takes an onslaught of viral particles to overwhelm the immune system, invade a cell, and start replicating. It’s generally thought that the higher a patient’s viral load — the more virus their cells are emitting — the more infectious the patient.

With COVID-19, at least some asymptomatic patients seem to be just as virally loaded as those with fevers, coughs, and breathing difficulties.

One Chinese study describes an infected 26-year-old who never developed symptoms but whose viral load, based on nose and throat swabs, “was similar to that in the symptomatic patients.”

Another Chinese study traced a family cluster of nine members. Among the eight who became infected, two never developed symptoms, and two were infected by members who had not yet fallen ill.

“Asymptomatic patients can still infect others,” the authors wrote, “These ‘silent patients’ may remain undiagnosed and be able to spread the disease to a large number of people.”

In cases of pre-symptomatic transmission, those infected appear to be most contagious in the two days or so before symptom onset; after that, viral load begins to decline.

One Chinese team, using a variety of models, reported that “infectiousness peaked on or before symptom onset” and estimated that between 44% and 52% of COVID-19 transmission occurs before illness.

It remains unclear whether asymptomatic or mild cases are as contagious as severe cases. However, to protect patients and healthcare workers alike, hospitals must take stealth transmission every bit as seriously as transmission from severely ill patients.  

“Just because you get the disease from someone with mild symptoms does not mean yours are going to be mild,” cautions Columbia University’s Jeffrey Shaman. “You could still end up in the I.C.U.”

How Asymptomatic Transmission Occurs

No doubt, asymptomatic transmission is contributing to the spread of COVID-19. Infected people who feel just fine are passing on the virus simply by talking or breathing — no sneezing or coughing necessary.

It may be enough for an infected healthcare worker, one who may never become ill or may develop a fever tomorrow, to chat with a colleague. It may be enough for her to sit on a bench and sigh, releasing microscopic viral particles that waft about the hospital, only to be inhaled by someone else or to land on a computer keyboard that someone else touches.

“We can’t assume that any of us are not potential vectors at any time,” says Carl Bergstrom, Ph.D., an American expert in emerging infectious diseases.

Though droplet and contact transmission may be driving the pandemic, evidence for aerosol transmission of SARS-CoV-2 is accumulating.

In multiple hospital studies, air samples have tested positive for SARS-CoV-2 — in hallways and in rooms where healthcare workers removed protective clothing after treating COVID-19 patients.

And now a study conducted at two Wuhan hospitals has found the virus was “widely distributed” in the air and on surfaces in both the ICU and general COVID-19 ward, “implying a potentially high infection risk for medical staff and other close contacts.”

What’s more, the authors found the transmission distance of SARS-CoV-2 particles may actually be 4 metres, more than twice the distance that heavier droplets can travel.

The authors don’t know whether the airborne load of SARS-CoV-2 was potent enough to transmit infection. But they do not advise taking any chances and recommend their findings be “used to improve safety practices.”

Throughout the pandemic, hospitals have been doing all they can to maintain hand hygiene and surface cleaning and to provide healthcare workers with sufficient protective gear. But gear shortages have been dire, hand hygiene is notoriously inadequate, and cleaning crews simply cannot keep up.

The best defence against stealth transmission of COVID-19 is the outdoors, where air currents can disperse infectious particles. But inside a hospital, the best defence is ultra-low-energy plasma technology by Novaerus, an important addition to ventilation and filtration.

Independent laboratory testing has proven Novaerus technology highly effective against MS2 Bacteriophage, a commonly used surrogate for SARS-CoV, reducing the airborne load by 99.99%. The company’s latest innovation, the Defend 1050 shows this reduction happening in just 15 minutes.

At hospitals worldwide, including in Wuhan, China, Novaerus portable units have been installed in ICUs and COVID-19 wards to help prevent transmission of the virus among healthcare workers and patients.

Novaerus units operate continually and are safe around the most vulnerable patients, including critically ill COVID-19 patients.

In the superbug era, Novaerus technology has become vital for hospitals fighting MRSA, Clostridium difficile, Aspergillus niger, and other lethal airborne pathogens.

Now, amidst the COVID-19 pandemic, ultra-low-energy plasma technology has become indispensable.