Yes, Covid-19 Aerosols Are Infectious, And More Dangerous than Droplets – Part 1

In 1981, seven American children contracted measles during a visit to the same doctor’s office.

Three of the children had never crossed paths with the 12-year-old source patient. One child arrived at the office an hour after the infected boy had left.

The outbreak caused a stir. At the time, public-health authorities believed measles was transmitted via large respiratory droplets, the kind generated by phlegmy coughs, and required contact within about 1 meter of an infected person.

So ingrained was this belief that a major medical journal, Pediatrics, deemed the outbreak an outlier, concluding that for measles, “airborne spread is unusual.”

Of course, today we know the opposite is true. Microscopic measles particles can remain airborne and infectious for up to 2 hours and can drift far and wide. In one case, an infected athlete transmitted the disease to spectators 100 feet (30.5 meters) away. The notion that measles is primarily contracted through contact with large droplets, rather than via tiny, inhaled aerosols, has been thoroughly debunked.

One year into the Covid-19 pandemic, that same theory has been debunked with respect to SARS-CoV-2 transmission, though infection-control measures have lagged behind the science.

In one regard, the evidence supporting aerosol transmission for Covid-19 is actually stronger than it is for measles: Viable SARS-CoV-2 has been captured via air sampling, a feat that has yet to be achieved with the measles virus.

In fact, only one study, published in 2016, long after experts declared measles airborne, has captured measles RNA in the air — a study its authors called “the first study to directly detect evidence of airborne transmission of measles.” Yet in that study, testing in cell cultures failed to detect viable measles virus.

By contrast, at least six air-sampling studies have isolated SARS-CoV-2 RNA. And one, conducted at the University of Florida, proved SARS-CoV-2 viral particles — captured as far as 4.8 meters from a Covid-19 patient — were viable.

“If this isn’t a smoking gun, then I don’t know what is,” asserts Linsey Marr, PhD, a Virginia Tech aerosol scientist who was not involved in the study.

Marr calls the results “unambiguous evidence that there is infectious virus in aerosols.”

The Florida study, piled atop volumes of other evidence pointing to aerosol transmission, has intensified calls for more robust infection control indoors — in hospitals, nursing homes, dental practices, and retail establishments.

With ultra-contagious SARS-CoV-2 variants now surging globally, the stakes could not be higher.

“It is very clear that aerosols play a considerable role in the transmission of Covid-19 and that we are unlikely to prevail against this pandemic unless we acknowledge that fact,” asserts Justin Morganstern, M.D., a Canadian emergency physician, in an evidence review.

While physical distancing and masks remain important, Morganstern argues, “We should be looking at the extra precautions we can add to stem the spread of this disease.”

Foremost among these precautions should be air filtration and dis-infection, say experts, including Kevin Fennelly, M.D., of the U.S. National Institutes of Health.

At hospitals and nursing homes, infection-control protocols are based on “old data and inferences,” Fennelly asserts in The Lancet Respiratory Medicine. Droplet transmission is not driving the pandemic, he argues, and precautions should be updated to “account for the predominance of small particles within infectious aerosols.”

Coronavirus in the Air

At the pandemic’s outset, health authorities made the same assumption about SARS-CoV-2 that they’d made, erroneously, about measles in the 1980s and tuberculosis in the 1950s: that aerosol transmission, if it happened at all, was “probably very rare.”

But that assumption soon began to wither.

Quickly, it became clear that asymptomatic carriers were spreading Covid-19 in huge numbers, without sneezing or coughing.

What’s more, scientists identified outbreaks — on cruise ships and bus rides, at choir practices and ski resorts, in call centres, restaurants, and shopping malls — that could not be explained by surface or droplet transmission.

Strengthening the case for aerosol spread, scientists captured SARS-CoV-2 genetic material on surfaces that patients could not possibly have touched, such as air outlet vents and air-handling grates.

Even more compelling, coronavirus particles were captured in the air — above flushing toilets, in hospital nurses’ stations and changing rooms, in hallways outside patient rooms, and inside patient rooms beyond 6 feet from the patients.

Still, questions persisted: Was the RNA viable? Could the captured particles actually invade a cell, replicate, and trigger infection? Or were they inert, harmless fragments of genetic material?

The answer was elusive because aerosols, microscopic and fragile, are easily damaged by the air-sampling process.

But the University of Florida team used new, more sophisticated technology, preserving SARS-CoV-2 RNA captured in the air 15 feet from a Covid-19 patient. The genome sequence of the collected virus matched the sequence isolated from the patient.

The study, says lead researcher John Lednicky, PhD, proved “conclusively” that viable SARS-CoV-2 particles, small enough to be inhaled, can linger in the air and pose a risk to those in the vicinity.

The study squelched doubt that Covid-19 can spread — and readily — via aerosols.

Part two coming soon.

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.

WellAir Announces Acquisition of UV Innovators and Appointment of Todd Pope as President and CEO

Todd M. Pope, Executive Chairman of UV Innovators appointed President and CEO of WellAir

WellAir’s flagship product, the Defend 1050, a portable air cleaning system which utilizes patented plasma-based technology, received U.S. FDA clearance in January 2021

WellAir, a leader in delivering clean air solutions to people around the world, today announced the acquisition of UV Innovators (“UVI”), a North Carolina-based developer of medical-grade handheld UVC disinfection technology. In addition, the company announced that Todd M. Pope, executive chairman of UV Innovators, has been appointed President and CEO of WellAir.

Creating an Industry Leading Disinfection Platform

WellAir’s mission is to mitigate airborne pathogens that lead to infectious diseases, including viruses, by delivering energy-efficient technologies that enable safe indoor spaces for the health and wellbeing of all individuals. The combination of WellAir’s innovative air cleaning technology portfolio along with UVI’s handheld UV surface disinfection device creates a best-in-class platform.

WellAir’s portfolio of products create an ecosystem for healthy indoor air, which have been independently proven to reduce viruses, bacteria, particulate, mold, and volatile organic compounds. The Company’s platform includes portable medical-grade air disinfection devices and HVAC-integrated systems. The Company’s flagship product, the Defend 1050 is the only portable air cleaning system to use NanoStrike technology, a patented plasma-based technology that inactivates airborne viruses and bacteria. The Defend 1050 recently received U.S. FDA 510(k) clearance, the only portable air cleaning system using NanoStrike technology to have achieved this designation. WellAir serves individuals and organizations across a wide variety of settings, including healthcare, education, and commercial.

UVI has developed the world’s first handheld instant UVC surface disinfection device, bringing a powerful and portable hospital-grade solution to all environments. The Company’s NuvaWave™ has been shown to be over 99.88% effective at destroying the most common and harmful pathogens in just one second, including SARS-CoV-2, the virus that causes COVID-19. NuvaWave technology is used by individuals and organizations across a wide variety of settings, including healthcare, education, hospitality, and sports and entertainment.

“Combining UVI’s handheld surface disinfecting device with WellAir’s best-in-class air cleaning platform creates a unique, broad spectrum and highly scalable solution to. enable safe, healthy, and productive spaces for all individuals,” said Bill McCabe, Chairman of the Board of WellAir. “I am excited to have Todd join WellAir and to lead the Company through its next stages of growth. His experience bringing innovative medical technologies to market on a global scale will be invaluable as we look to fulfill our mission to protect indoor spaces for all individuals.”

“We are thrilled about the combination of WellAir and UVI, who have a shared mission of managing infectious diseases and creating safe environments across the globe,” said Steve Wordsworth, UVI’s sole investor. “I believe this acquisition will help UVI and its technology reach its highest potential and bring the benefits of medical-grade surface disinfection to the greatest number of people,” commented UVI board member Andy Blanton.

Appointment of President and Chief Executive Officer

Upon closing, UVI’s Executive Chairman of the Board, Todd M. Pope will serve as WellAir’s President and Chief Executive Officer. Mr. Pope brings significant healthcare industry leadership experience to the Company. Prior to joining UVI as its Executive Chairman, Mr. Pope served as a Resident operating partner at Revival Healthcare Capital, a healthcare-focused private equity firm. Before joining Revival, Mr. Pope served as President and Chief Executive Officer of TransEnterix, a publicly traded surgical robotics company. Mr. Pope has also held leadership roles at Johnson & Johnson and Boston Scientific. In addition, he currently serves as a Board Member with AdvaMed Accel.

“I am proud and energized to join the WellAir team at such an important inflection point, just weeks after receiving FDA clearance for the Defend 1050,” said Mr. Pope. “COVID-19 has put a spotlight on the need for advances in high-powered chemical-free disinfection and air purification technologies, in healthcare settings and everywhere people come together. The combination of these two companies creates a broad, innovative solution to meet the needs of organizations and industries around the world to enable safer living, working, and healing spaces.”

In addition to Mr. Pope, Dr. Nick Medendorp, UVI’s Chief Executive Officer and Co-Founder, and Steve Grenon, UVI’s Chief Technology Officer and Co-Founder, will join WellAir to serve in key executive roles.

About UV Innovators

UV Innovators, LLC was founded by Dr. Nick Medendorp, Steve Grenon and Todd M. Pope to develop a medical-grade UVC handheld to combat pathogens that cause hospital-acquired infections. To help combat the COVID-19 outbreak, UV Innovators accelerated the development of its UVC disinfection solution to help all businesses in need of powerful, portable and fast solutions.

The Fallacy of the 2-Metre Rule – Part 1

“People think they are protected indoors and they’re really not”

Six months into the Covid-19 pandemic, an American governor recounted a visit she’d made to a local business. Upon entering, she didn’t wear a mask, she told her TV audience, “because I was socially distant.”

Only when she ventured near employees did she slip on her mask. Her message: Stay 6 feet (2 metres) apart from others. “But if you can’t, have a mask ready, and put it on.”

For nearly a year, the 6-foot/2-metre rule has been invoked by officials worldwide and gained traction with the public.

And yet, scientists say, the rule is misleading — based on an erroneous understanding of aerosol science and insufficient to curb Covid transmission.

“It has been biggest disservice that public health groups have given,” Robert Schooley, M.D., an American infectious-disease specialist told a panel at an international workshop on Covid-19 transmission. “It never should have come out of anybody’s mouth.”

Early on, experts assumed SARS-CoV-2, like the first SARS coronavirus, was spread almost entirely via close contact. They assumed virus-laden droplets, launched by a sneeze or a cough, were too heavy to travel beyond 2 metres, so physical distancing would largely control transmission.

A mountain of research has debunked these notions.

We now know large droplets can journey beyond 2 metres and, at any rate, play just a partial role in the spread of Covid-19. Often, the disease is transmitted via far smaller particles, known as aerosols, that can sail across a large room and hover for hours, only to be inhaled by vulnerable people.

“Indoors, those distance rules don’t matter,” says Robyn Schofield, PhD, an atmospheric chemist at Melbourne University in Australia. “People think they are protected indoors and they’re really not.”

The evidence documenting long-range aerosol spread of Covid-19 has major implications for hospitals, restaurants, pharmacies, retail spaces, offices — any enclosed, high-traffic space.

In the short term, the science makes a strong case for face coverings. However, it’s impossible to eat, drink, or have your teeth cleaned while wearing a mask, and at some point, following the Covid-19 vaccine rollout, mask guidelines may disappear.

SARS-CoV-2, however, will remain in our midst, along with influenza and other airborne pathogens that continually endanger lives. In addition, new airborne viruses and strains of antibiotic-resistant bacteria are certain to emerge.

“Distance alone will never solve the aerosol problem,” says Jose-Luis Jimenez, Ph.D., a University of Colorado chemist. “If you are in the same room, you can get infected.”

That’s why building operators must augment their current infection-control precautions, upgrading ventilation, filtration, and air dis-infection technology.

The Dubious Origin of the 2-Metre Rule

Back when commercial flights were divided into smoking and non-smoking sections, it didn’t much matter where you sat; before long, the smell of smoke would permeate the plane.

In the same way, particles carrying SARS-CoV-2, which are similar in size to smoke particles, can permeate a room.

“High concentrations of smoke do not usually build up outdoors because the smoke is quickly diluted by the large volume of air. This is also true for respiratory droplets,” explains at team of mechanical engineers at Clarkson University in New York.

But indoors — where the odds of Covid transmission are 18.7 times greater than outdoors — the picture is quite different: Lack of ventilation “allows the concentration of small airborne respiratory droplets to build up over time, reaching all corners of a room.”

Would a 2-metre separation, even if bolstered by a plexiglass shield, block cigarette smoke?

“The answer is no,” William Ristenpart, PhD, a University of California chemical engineer, told the international Covid workshop panel. “[SARS-CoV-2] aerosol particles behave the same way.”

Yet restaurants and shops often operate as if coronavirus particles either vanish within 2 metres or can be stopped by plastic dividers. Restaurants place tables 2 metres apart, and offices do the same with desks. See-through barriers have been installed in karaoke bars and countless retail establishments.

Surprisingly, these precautions rely on a model of disease transmission that dates back nearly a century.

It was 1934 when William Wells, an American scientist, published a paper dividing infectious respiratory particles into two categories: large and small. Wells believed small droplets (less than about 10 microns) evaporate rapidly while large ones quickly succumb to gravity.

“He found that the farthest any droplets travelled before either settling or evaporating was about 6 feet,” the Clarkson team recounted.

But Wells didn’t have the high-speed video to deconstruct the explosive aftermath of a sneeze or a sigh.

Turns out, respiratory droplets come in a wide range of sizes, not just “small” and “large,” and they can drift far and wide.

Once expired, droplets travel in clusters, and the warm, moist cloud enveloping the droplets allows the tiniest among them to “evade evaporation” for long periods, explains Lydia Bourouiba, PhD, an expert in fluid dynamics at the Massachusetts Institute of Technology.

“The cloud is in fact moving forward, trapping its payload over wide ranges of distances,” says Bououiba, who films exhalations with cameras running at thousands of frames per second. “There is really no barrier of 1 to 2 meters.”

Even large droplets can travel beyond 2 metres. “You have to get up to a size of 30 microns for something that won’t travel more than 2 metres,” reports Linsey Marr, PhD, an environmental engineer at Virginia Tech university.

And that’s in stagnant air. Under high air velocity, Marr says, “a 30-micron droplet can travel 7 to 8 metres.”

A 5-micron aerosol takes about half an hour to drop to the floor and, under certain conditions, can travel over 100 metres, according to Marr. Air currents in a room play a big role in how far aerosols can journey.

Yet the 2-metre theory continues to influence, even dictate, public-health guidance.

“The idea of 6 feet is to keep you out of each other’s large droplets, but that doesn’t do anything for the background aerosols that might be in the room,” says Marr.

Read part two here.

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.

The “Pig Pen” Effect: When Motion, Not Breathing, Spreads Infection

Back in the 1950s, cartoonist Charles Schulz introduced a new character into his world-famous Peanuts strip: Pig-Pen, an amiable boy known for the cloud of dirt and dust that follows him everywhere.

“I’m a dust magnet!” Pig-Pen declared.

In truth, we’re all dust magnets, and this fact may play a role in the airborne spread of disease.

Research shows airborne pathogens, having landed on surfaces, can be kicked back up into the air by human activity — walking a hallway, opening a door, removing a lab coat. These dangerous microbes, riding on dust particles, can then be inhaled or swallowed.

Influenza, norovirus, and Clostridium difficile are likely transmissible in this manner, and SARS-CoV-2 may be as well. Pig-Pen himself has been invoked in scientific discussion on transmission of the flu and Covid-19.

“Aerosols can settle to the ground, where they are resuspended into air just by us walking around,” Linsey Marr, Ph.D., an American environmental engineer, explained at an international workshop on Covid transmission. “[This causes] a secondary opportunity for transmission by aerosols. We call this the Pig-Pen effect.”

We know that sneezing, coughing, singing, talking, and mere breathing can transmit Covid-19. It’s assumed that SARS-CoV-2 also can be transmitted via contaminated surfaces, known as fomites. Now, evidence suggests another possible route: “aerosolized fomites” — in other words, the Pig-Pen effect.

“We showed that just rubbing a [flu-]contaminated paper tissue aerosolizes several thousand micron-scale particles,” William Ristenpart, PhD, a chemical engineer at the University of California, reported at the international workshop. “What this points to is, there are other ways a virus can get into the air.”

Ristenpart’s studies on flu spread among guinea pigs points in the same direction, as does coronavirus research conducted at Wuhan hospitals.

Ristenpart calls aerosolized fomite transmission “underappreciated” and notes that his team’s findings, published in Nature, have important implications for public health, including the spread of Covid-19.

This is especially true for hospitals, nursing homes, businesses — any high-traffic where air is shared. Certainly, masks can reduce the number of particles exhaled by infected people, and enhanced surface cleaning can help contain spread via fomite. However, controlling disease transmission via the Pig-Pen effect requires additional precautions, including continual air dis-infection.

Walking Kicks up Millions of Particles Per Minute        

In a slide shown at the international Covid-19 workshop, three women, one of them infectious, stand in a room filled with virus-laden dust particles. The particles, some of them resuspended by footsteps, are represented as red dots, to help us imagine what we can’t see.

But those scattered red dots don’t adequately represent the swarm of aerosols typically kicked up by human activity.

“An adult walking across the floor can resuspend 10 to 100 million particles per minute, while tossing and turning on a mattress can stir-up similar levels of microbial-laden dust,” explains Brandon Boor, PhD, an aerosol scientist at Purdue University in the United States.

In a study conducted with Finnish microbiologists, Boor found that in 1 minute of crawling across a carpet, 1,000 to 10,000 resuspended particles will deposit in the infant respiratory system.

Boor is another scientist who references Charles Schulz in his work, noting the cartoonist’s portrayal of Pig-Pen as being perpetually enveloped by a dust cloud is “quite accurate.” Boor calls resuspension of particles via human movement a “major indoor source of biological particulate matter,” including bacteria, fungi, and allergens.

Well before the emergence of SARS-CoV-2, research suggested infectious aerosols could be bandied about by human activity.

In a British hospital study, for example, researchers sampled the air near patients infected with Clostridium difficile. The bacteria, known to cause nausea and severe diarrhoea, has become a deadly threat in hospitals due to the emergence of virulent, antibiotic-resistant strains.

What the study found: Over a 10-hour period, airborne C. difficile was most commonly detected during periods of activity, such as food delivery, ward rounds, or bedding changes.

“Activities known to liberate particles into the air, such as bed making and curtain drawing” may contribute to the spread and aerosolization of C. difficile, the scientists concluded.

Unlike SARS-CoV-2 or influenza, C. difficile is not a respiratory pathogen; people become infected by swallowing airborne particles or touching contaminated surfaces and then touching their mouths. Given that patients’ clothing, bedding, and skin are often teeming with C. difficile spores, aerosolization of surface particles could be quite dangerous.

Norovirus, another virulent and highly contagious stomach bug, can be resuspended off the floor, as well.

A Brazilian research team, reporting in the Journal of Hospital Infection, evaluated protocols for cleaning floors contaminated with norovirus. The scientists detected Norovirus particles in 27 of 36 post-cleaning air samples, concluding the virus “can be aerosolized during floor cleaning, and its particles may be inhaled and then swallowed or can settle on surfaces.”

Can SARS-CoV-2 Spread via the Pig-Pen Effect?

It’s clear that pathogens can be dislodged from surfaces and resuspended into the air. But can these “liberated” aerosols actually cause infection?

Apparently so, according to a clever University of California study on the spread of influenza among guinea pigs.

The study involved 12 pairs of guinea pigs, housed in separate but adjoining cages. One rodent was immune to influenza, having previously been infected; its partner remained vulnerable to the disease. Using a paintbrush, researchers applied liquified influenza to each immune rodent’s fur, ears, and paws.

The cage design prevented contact between the rodents while directing air to flow from the immune rodent’s cage to its partner’s cage. This left just one plausible infection source for the vulnerable rodents: viral particles launched airborne by the activity, rather than exhalation, of their immune partners.

The results surprised even the scientists: After one week, 3 of the 12 vulnerable guinea pigs had contracted influenza.

Based on the study, co-author William Ristenpart disputes the assumption that infectious airborne flu particles must come from breathing, coughing, or sneezing or from aerosol-generating medical procedures.

“We now provide direct experimental evidence that . . . aerosolized fomites from a virus-contaminated environment can spread influenza viruses through the air,” his team wrote.

In the same paper, Ristenpart reported that viable influenza particles can be aerosolized from paper tissue. His team found that crumpling, folding, and rubbing dried, contaminated tissue released up to 900 particles per second and that the particles were “in the respirable range.”

If influenza can be spread via the Pig-Pen effect, can SARS-CoV-2?

Ristenpart’s team suspects so. Their guinea-pig study references research conducted at two Wuhan hospitals dedicated to Covid-19 care.

In one study, researchers captured air samples in several locations throughout the hospitals. They found the highest concentration of coronavirus RNA not in Covid wards or patient isolation rooms but rather in rooms where medical staff changed out of their gowns, masks, and other gear.

The suspected source: “resuspension of virus-laden aerosols from the surface of the protective apparel worn by medical staff while they are removing the equipment.”

The virus-containing aerosols were small enough to remain suspended in the air for long periods and to be inhaled.

Continual Air Dis-infection: Critical for Limiting Infection Spread

As Brandon Boor notes, the resuspension of dust is “an inherently transient process,” changing minute by minute based on human occupancy and movement patterns.

What this means for hospitals, nursing homes, retail, or office spaces: air dis-infection units must be running 24/7.

Surface cleaning is important, but pathogens rebound quickly. One study found hospital bed rails would have to be professionally cleaned every 2 hours to keep harmful bacteria to a safe level.

And while masks effectively limit emissions of dangerous particles, public mask-wearing regulations are often flouted, and the rules will disappear, at any rate, when a Covid-19 vaccine becomes widely available. SARS-CoV-2, however, will continue to float about, along with influenza, norovirus, and countless other pathogens that contaminate our shared air.

In the indoor environment, controlling infection will always require multiple strategies. Critical among these is 24/7 air dis-infection, particularly NanoStrike technology from Novaerus.

Novaerus units generate an electrical discharge, known as ultra-low energy plasma, that destroys viral, bacterial, and fungal particles. Within nanoseconds, the devices obliterate pathogens into inert, harmless debris, expelling clean air back into the room.

Unique among air-disinfection devices, NanoStrike technology leaves behind no by-products and is safe to operate continually even in ICUs and operating theatres.

Independent lab tests have confirmed the technology destroys MS2 Bacteriophage, a surrogate for SARS-CoV-2, as well as influenza, Clostridium difficile, and numerous other airborne pathogens. The same technology also wipes out the pollutants, such as volatile organic compounds (VOCs), that cling to dust particles.

In an early Peanuts strip, Pig-Pen is described as the only person who could manage to get dirty while walking in a snowstorm. He simply can’t shake off the dust.

In reality, none of us can, which makes Novaerus technology essential for hospitals, schools, pharmacies, and pubs alike.

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.

The Massive Responsibility to Safeguard Students: Why Schools Must Disinfect the Air – Part 2

Read part one of this blog here.

Ventilation and Filtration: School Buildings Must Do More

Some school websites do discuss ventilation and air filtration, critical strategies for controlling airborne spread. But here again, actions fall short.

Open windows are a simple way to reduce airborne concentration of coronavirus particles, but many classrooms have no windows. In others, the windows are bolted shut. Even when windows are operational, they’re often kept closed to keep out allergy-inducing pollen or blasts of cold air.

Schools are notorious for ventilation deficiencies. A  recent analysis documented ventilation problems in 60% of New York City schools with ventilation reports. Well before the emergence of Covid, the U.S. Environmental Protection Agency (EPA) reported poor indoor air quality in U.S. schools may pose a “serious health threat” to students and staff.

The EPA was referring to airborne contaminants emitted by a wide range of biological and chemical sources, from mouldy ceiling tiles to cockroach dander to idling school buses and vaping devices.  But the ventilation deficiencies that expose students and staff to pollutants also leave them vulnerable to SARS-CoV-2.

So do shortcomings in air filtration. At many schools, the HVAC systems just aren’t equipped to handle high-level systems. As one American college concedes, adopting a more powerful filtration system “could very well cause system failure.” Even stand-alone HEPA filters won’t capture 100% of coronavirus particles, some of which are 900 times smaller than the width of a human hair.

One toxicologist, a member of the American Industrial Hygiene Association, described school filtration systems as “designed to control body odour, to be honest.” SARS-CoV-2, he noted, is a highly contagious aerosol. “We’re being asked to suspend disbelief and believe that buildings were designed to protect us against infections. You’re going to have to do more.”

What more can be done?

Ultraviolet (UV) light technologies, designed to kill viral particles that slip through filters, are often touted as alternatives. But UV rays pose their own health risks, which is why they’re used to disinfect subway trains after hours and elevators not in use. UV light is not a practical or safe way to destroy coronavirus particles hovering in classrooms.

A far better solution is an ultra-low energy plasma-based nanotechnology from Novaerus, called NanoStrike®.

Powered by NanoStrike, Novaerus air dis-infection devices are unobtrusive, available in three different sizes, and can be easily placed or mounted in classrooms, dorm rooms, restrooms, school nurse’s offices, campus health centres, and other high-risk spaces.

The devices house a series of coil tubes that generate an electrical discharge, not unlike the plasma emitted by lightning. A high-quality fan draws contaminated air into the chamber where, in nanoseconds, the DNA of pathogens becomes stretched by the plasma and explodes into inert, harmless debris. Clean air is then expelled back into the room.

Unique among air-disinfection devices, NanoStrike technology leaves behind no harmful by-products.

Novaerus devices are so safe, even for the most vulnerable populations, that they are commonly deployed in hospital ICUs, operating theatres, and emergency rooms. Designed to protect both patients and medical staff from infection, the devices run 24/7. With a highly infectious virus such as SARS- CoV-2, continual air disinfection is critical.

The same sleek, white metal boxes can now be found in universities and schools alike.

NanoStrike technology, proven highly effective by independent lab testing, has long been used to fight influenza, norovirus, measles, MRSA — any number of viral and bacterial diseases. Tests also have confirmed the devices destroy airborne toxins such as VOCs and fine particulate matter.

Now, lab tests confirm NanoStrike technology can reduce airborne load of MS2 Bacteriophage, a virus used as a surrogate for SARS-CoV-2, by 99.99% in just 15 minutes.* Hospitals worldwide, from Wuhan to Budapest, have installed the units in their Covid wards.

Novaerus portable devices, powered by NanoStrike Technology can help to remove airborne viruses which travel in tiny aggregated droplets that can linger for hours before they settle on surfaces.

Schools Must Prioritize Air Disinfection

The stakes for schools have never been higher. At least 6 American school teachers died from Covid-19 in the weeks after schools re-opened. Mississippi reported over 600 cases among teachers and staff.

In Italy, concerns were raised as the country with the oldest teaching workforce in the EU returned to school. More than half of primary and secondary school teachers in Italy are over the age of 50, with 17% over 60.

Schools are working hard to keep staff and students safe. At the same time, administrators and building operators are inundated with conflicting guidance — from government authorities and public-health experts — on how best to minimize coronavirus spread. Recently, the CDC has updated its guidance on how COVID-19 spreads, acknowledging that the coronavirus can spread via airborne transmission.

“People have prevention fatigue,” says Dr Emanuel Goldman, the Columbia microbiologist. “They’re exhausted by all the information we’re throwing at them. We have to communicate priorities clearly.”

In schools, Dr Goldman asserts, the top priority must be air disinfection. An investment made during the pandemic will pay dividends in the aftermath.

“Covid-19 is not the first — and will not be the last — infectious disease to threaten our society,” says Harvard’s Joseph Allen, co-author of Healthy Buildings. “School building systems, in general, have historically been underfunded, under-ventilated, and under-prepared.”

By deploying Novaerus NanoStrike technology, schools will find themselves prepared for future waves of Covid-19 and the inevitable outbreaks of other highly infectious diseases.

*The Novaerus Defend 1050 air dis-infection unit was shown to reduce the virus by 99.99% in 15 minutes.

The Massive Responsibility to Safeguard Students: Why Schools Must Disinfect the Air – Part 1

Scan the website of any school that has reopened in the Covid-19 era, and you’ll find a litany of “enhanced disinfection protocols.”

Cleaning schedules for whiteboards, light switches, and cafeteria microwaves. Lists of government-approved carpet disinfectants. An accounting of “hypochlorous acid disinfectant wipes” in staff restrooms.

Keep clicking and you’ll find the school’s “physical distancing framework” — protocols for university shuttles and chemistry labs, guidelines for classroom desk dividers and elevator occupancy.

As schools welcome students and teachers back to class, they are seeking to inspire confidence in their Covid-19 precautions. But just how effective are all these measures?

It’s a high-stakes question. Already, more than 50,000 coronavirus cases have been reported by U.S. colleges, U.S. pediatric cases have hit half a million, and outbreaks have forced schools worldwide — from Wales to Israel to the United States — to close just days after re-opening.

In Berlin, Germany, coronavirus cases were reported by at least 41 schools a fortnight after the capital’s 825 schools reopened.

As for the answer: Scientists say schools are largely missing the boat.

“Surfaces are not really the problem,” asserts microbiologist Emanuel Goldman, Ph.D., of Rutgers New Jersey Medical School. “What [schools] really should be doing is focusing on the main routes of transmission of this disease, which is breathing.”

That’s why physical distancing measures indoors are of limited value, too.

“Distance alone will never solve the aerosol problem,” says Jose-Luis Jimenez, Ph.D., a University of Colorado chemist. “If you are in the same room, you can get infected.”

It’s well documented that coronavirus particles can linger in the air and travel across a room. To protect students and staff from inhaling these particles, schools must focus less on disinfecting desks and more on disinfecting the air.

Of course, SARS-CoV-2, the virus that causes Covid-19, isn’t the only pathogen swirling about campuses. School buildings are reservoirs for a range of airborne viruses and bacteria, as well as asthma-inducing mould spores and pollutants such as volatile organic compounds (VOCs). The coronavirus pandemic has only underscored the need for schools to deploy air-disinfection technologies year-round.

“They’re not only going to be helpful for Covid-19 but for next year’s flu season,” says David Brenner, Ph.D., a Columbia University physicist.

And not just to minimize influenza spread but also to quell the inevitable outbreaks of norovirus, common cold, and even high infectious diseases such as measles, now making a comeback around the world. As one American epidemiologist noted, once the Covid pandemic fades, schools will continue to have “the massive responsibility to safeguard the health and well-being of their students.”

Why Surface Cleaning and the 2-Metre Rule Fall Short

Scientists agree surface cleaning plays a minor role, at best, in controlling transmission of SARS-CoV-2. In fact, elaborate disinfection measures have been dubbed “hygiene theatre,” a feel-good display of concern that provides little actual protection.

School surface protocols emerged after early research suggested SARS-CoV-2 can survive for days on metal and cardboard. But recent analyses found those studies used exaggerated conditions. As Columbia’s Dr Goldman notes, up to 100 people would need to sneeze in precisely the same spot to match some of the experimental conditions.

The early studies, Goldman argues, “stacked the  deck to get a result that bears no resemblance to the real world.”

What is happening in the real world: aerosol transmission, often by young people with no symptoms. A student who feels top-notch can,  merely by asking a question, emit infectious particles light enough to sail across a classroom, even a lecture hall. A single minute of loud talking could launch over 1,000 virus-containing droplets.

Depending on the conditions, SARS-CoV-2 can travel well beyond 2 metres, the default distancing guidance for schools. In one hospital study, scientists captured viable airborne coronavirus particles nearly 4.8 metres away from a hospitalized Covid patient.

The guidance dates from 19th-century research suggesting 6 feet (approximately 2 metres) was as far as microbe-laden droplets could travel. Today’s more sophisticated studies, using laser-light technology, demonstrate that droplets exist in a range of sizes, cluster in invisible clouds, and can travel much farther indoors.

Six feet is a fine number, but we need to convey that this is a starting point,” says Linsey Marr, Ph.D., a Virginia Tech environmental engineer.

Case reports bolster the evidence. For example, in a well-known Washington choir practice, one singer spread SARS-CoV-2 as far as 13.5 metres; 53 of 61 choir members became infected, and two died.

No doubt infectious particles can waft about classrooms, hallways, staff lounges — anywhere on campus, including restrooms.

“When you flush a toilet, the churning and bubbling of water aerosolizes faecal matter,” explains Joseph Allen, Ph.D., director of the Healthy Buildings program at Harvard’s school of public health. “You’re breathing in toilet water and whatever is in that toilet water — including viruses and bacteria.”

SARS-CoV-2 may well be among those viruses.

In hospital studies, traces of coronavirus RNA have been detected in air samples collected near toilets of Covid-19 patients. Bioaerosols may linger for more than 30 minutes after a flush, other research has found. What’s more, compared to toilets with lids, lidless toilets — standard in elementary and secondary schools — increase the risk infectious particles will escape.

Enforcing the 2-metre rule won’t lower the odds that a student or staff member might inhale those particles. Neither will scrupulous disinfection of door handles and microwaves.

All in all, experts concur, school Covid precautions are falling short. Indeed, one American epidemiologist called the priorities at her own child’s school — one-way hallways, frequent sanitizing, temperature checks — “dangerously misdirected.” Airborne coronavirus spread, she lamented, was “absent from the conversation.”

Read part two here.