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.