TWe finally know how COVID-19 spreads, years after it started. Infected persons inhale tiny invisible particles called aerosols. They do not drop to the ground quickly, and instead move through the air much like cigarettes. These aerosols may infect other people if they are breathed in, be it in shared air or in close quarters. However, the process of accepting overwhelming scientific evidence about how COVID-19 spread proved to be too difficult and complicated. Even today, the updated guidance and policies of how to protect ourselves remain haphazardly applied, in part because of one word: “airborne.”
The response to the pandemic was shaped by this fundamental misinterpretation of the virus, which continues to be disastrous today. It is still evident in surface cleaning protocols, which many people have maintained even though they are not wearing masks. The key reason for this error is simple. In hospitals, the word “airborne” is associated with a rigid set of protective methods, including the use of N95 respirators by workers and negative pressure rooms for patients. They are costly and legally mandatory. There was a shortage of N95s at the beginning of the pandemic, so it would have been difficult, if not impossible, to fully implement “airborne” precautions in hospitals.
Because of the specific meaning of the term in hospitals, longstanding misinformation about the nature of airborne transmission, and the underappreciation and importance of it, public health officials were reluctant to use the word. As one article put it, “They say coronavirus isn’t airborne–but it’s definitely borne by air.” Because the word “airborne” was off-limits, it felt like we showed up to a basketball game thinking it was a boxing match.
During a press conference in February 2020, the Director-General of the World Health Organization said, “This is airborne, corona is airborne,” although a few minutes later, he corrected himself, “Sorry, I used the military word, airborne. This meant that the virus could spread through droplets and respiratory transmission. Please take it that way; not the military language.” In March, W.H.O. W.H.O. denied that Covid-19 had been airborne and posted on social media, “FACT: #COVID19 is NOT airborne,” and calling it “misinformation.” We and our colleagues, scientists and engineers who have studied airborne particles for our entire careers, met with W.H.O. We met with W.H.O. in April 2020 in order to raise our concern about airborne transmission being important for the spread COVID-19. W.H.O. W.H.O.
The U.S. Centers for Disease Control avoided this word, and rather tied themselves in knots to try to describe transmission. We were eventually heard but lost the initial pandemic period, which was when the virus could be stopped more easily and everyone was attentive and willing to adopt new protection behaviors. This virus made it so easy to instil protections like handwashing and surface disinfection that they are almost unusable. For transmission to increase, plexiglas barriers cost billions. In the course of two years the agencies began to recognize the possibility that the virus can be transmitted through air. W.H.O. became the first agency to do so in December 2021. finally used the word “airborne” on one webpage to explain how COVID-19 spreads between people, although the organization’s social media posts continue to completely avoid the word. C.D.C. continues to ban the use of this word.
It is not unusual to talk freely about waterborne, foodborne and bloodborne diseases. If even President Trump knew in February 2020, “You just breathe the air, and that’s how it’s passed,” why wasn’t the public told clearly the virus was airborne? The medical community believes that colds and flus are spread mostly by small droplets. It is very difficult to prove that a disease has been airborne. In the past, transmission by air has often been linked to long distances beyond 6 feet. These occurrences can be difficult to verify for rapidly spreading viruses because our observation at the time were restricted by long-standing practice that limits contact tracing to people within 6 feet.
Learn More: Clean Indoor Air Properly to Avoid COVID-19
The best evidence of transmission has been found in hospitals. Hospitals have better ventilation, so there is less chance for airborne infection. Ventilation is essential to remove the virus from the atmosphere and keep it from building up over time. This reduces the chance that an individual will inhale enough of the virus to infect others. We and our fellow colleagues tried to prove that the pandemic was airborne, and public health professionals began to realize that this could happen in certain situations. What they might not have realized is that, relative to hospitals, nearly all other buildings—homes, schools, restaurants, and many workplaces and gyms—would qualify as such special situations. These buildings might have indoor air replaced by outdoor air at most once an hour. Hospitals, however, are governed by a ventilation rate of 6 to 15 air changes per hour for patient rooms, and 15 per hour for operating rooms.
We have studied viruses in the air long enough to understand that “airborne” is a trigger word in healthcare, yet we found it maddening that the word was off-limits during a pandemic. It was okay to talk about aerosols but not to say “airborne” or explain “like smoke,” even though it would have been far more effective for communicating with the public. The word means anything that’s in the air. It can be a kite, pollen, or other similar term to the public. The situation is like trying to explain a carcinoma diagnosis to a patient without using the word “cancer.” Using the word earlier in the pandemic would have facilitated the implementation of more effective mitigation strategies, such as Japan’s 3Cs—avoid close contact, avoid crowds, and avoid closed, poorly ventilated settings—instead of focusing so much on 6-foot distancing and surface cleaning. This might also have helped to reduce resistance to masks.
Medical science should not hold the sole right to use the term airborne. To reduce confusion in communication, it is possible to modify the classification of the precautions used for infection prevention in hospitals. Rather than affixing specific words to the current categories—contact, droplet, and airborne—hospitals could assign numerical levels (e.g., 1, 2, 3, 4…) for different sets of precautions, such as those used for biosafety procedures in laboratories. The words could be used as they are, without being associated with any regulatory requirements.
It is clear from the outside that Covid-19 has been spread by a medical-centric, traditional approach. This may sound self-serving. we need to recognize that broader expertise beyond medicine is required for public healthIt is essential to combat an airborne virus. We, the two authors, know almost nothing about what happens to a virus when it’s inside your body nor how to treat it, but we do know how a virus behaves in the environment—whether indoors or outdoors—and how to remove it. These are the fields of aerosol science, mechanical engineering and atmospheric science. They study the movements and control of particles and gases in the environment. In our response to the pandemic, this type of expertise was neglected.
It is a great thing to see that the White House recognizes the importance indoor air quality and airborne disease through the Clean Air in Buildings Challenge, which forms part of its National COVID-19 Preparedness plan. This is an encouraging start but regulations and additional funding are needed in order to ensure clean air quality in buildings. Building operations account for approximately 30% of all greenhouse gas emissions. We need to figure out the best way to achieve this efficiency.
We can’t let “airborne” be a dirty word. Instead, we should increase public awareness about the health and safety of the air we inhale.
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