Earlier this month, the World Health Organisation (WHO) acknowledged that the Coronavirus can also be airborne. After denying for more than a year, the WHO finally updated the mode of Covid-19 transmission and said that the disease can be an airborne threat. It said, “the virus can also spread in poorly ventilated and/or crowded indoor settings, where people tend to spend longer periods of time. This is because aerosols remain suspended in the air or travel farther than 1 metre (long-range)”. For almost a year now, scientists all over the world have known that the SARS-CoV-2 can be airborne for a short distance for some time, but the WHO had refused to acknowledge that.
It may be noted that Centers for Disease Control and Prevention (CDC) of the USA had also admitted earlier this month that the Covid-19 virus can be airborne, after denying the same for a year.
On March 28 2020, the WHO, the global health watchdog, took to social media to put out a post, “FACT: #COVID19 is NOT airborne”. In its post, the WHO claimed that the coronavirus is mainly transmitted through droplets generated when an infected person coughs, sneezes, or speaks. For the scientists of WHO, Covid-19 was not airborne, and one could not contract the disease if they followed necessary protocols.
Linsey Marr, an aerosol scientist at Virginia Tech and an infectious disease expert, had her doubts regarding WHO’s so-called fact-check. For Marr, who had analyzed the initial results of the Covid-19 outbreak in China, it looked like the virus may stay in the air for longer, infecting anyone who breathed in enough of it. For people indoors, that posed a considerable risk. Soon, Marr joined with 35 other aerosol scientists to try and warn the WHO it was making a big mistake.
According to a detailed report by website – The Wired, for the next few days, the scientists analyzed the list of superspreading events in restaurants, call centres, cruise ships, and a choir rehearsal, instances where people got infected to Covid-19 even when they were far away from a contagious person. The incidents contradicted the WHO’s main safety guidelines, i.e., keeping 3 to 6 feet of distance between people and frequent handwashing.
If SARS-CoV-2 travelled only in large droplets that immediately fell to the ground, as claimed by the WHO, then how would people far away from each other caught the infection, the scientists pondered. They argued that the infectious air was the reason for the infection. However, the WHO’s experts were in no mood to listen to these scientists. To declare Covid-19 could well be airborne, the scientists wanted more direct evidence, which could take months to gather. Meanwhile, thousands of people were falling ill every day as the virus was abundant in the air.
Lidia Morawska, a revered atmospheric physicist, also tried to explain how far infectious particles of different sizes can travel. Shockingly, WHO experts abruptly cut her off, arguing that she was wrong.
As per Marr, Morawska has been advising WHO on the impacts of air pollution for over two decades. Interestingly, the organization has accepted her research on air pollution to understand similar particles of many sizes can hang aloft, travel far, and be inhaled. For the WHO’s advisers, the same laws of Physics strangely did not apply to virus-laced respiratory particles. To them, the word ‘airborne‘ only meant that particles smaller than 5 microns.
For Marr, the beginning of a global pandemic was not a good time to pick a fight with WHO. But, the reluctance of WHO to listen to experts and banking on outdated science that concerns public health policy had angered Marr. She had to get through to them, but first, she had to understand why they were failing to convince the WHO on Covid-19 being airborne.
According to scientists, almost all respiratory infections transmit through coughs or sneezes as bacteria and viruses quickly spread by falling and sticking to any surface within a distance of 3 to 6 feet. If these droplets come in contact with the nose or mouth, they can cause an infection. Only Measles and tuberculosis transmit a different way, an exception to the above rule. They are described as “airborne” as those pathogens travel inside aerosols, microscopic particles that can be alive for hours and travel longer distances. They can spread when contagious people breathe.
WHO relied on ‘5 micron’ classification to decide whether Covid-19 was airborne or not
As per Marr, the distinction between the droplet and airborne transmission has enormous consequences. To prevent droplets, one has to wash hands frequently with soap and water regularly. However, to fight infectious aerosols, the air itself is the enemy, which means setting up expensive isolation wards and providing N95 masks for all medical staff. The distinction between droplets and airborne is based on their length, i.e., at 5 microns. A micron is a unit of measurement equal to one-millionth of a meter.
By this definition, any infectious particle smaller than 5 microns in diameter is an aerosol, anything bigger than the size is a droplet. To her shock, the WHO and the US Centers for Disease Control and Prevention also keep the ‘5 microns’ as the basis to define whether a particle is a droplet or aerosol dichotomy toggled.
According to Marr, this is a problem. “The physics of it is all wrong,” Marr says as she explains how things move through the air. “Reality is far messier, with particles much larger than 5 microns staying afloat and behaving like aerosols, depending on heat, humidity, and airspeed. I’d see the wrong number over and over again, and I just found that disturbing,” Marr expresses her anguish.
The error meant that the medical community had a distorted picture of how people might get sick, the aerosol scientist contends. Marr decided to collect some data of her own. Marr found that droplets were small often stay aloft for hours, and it was enough of it to make people sick.
Despite all her efforts, Marr could not convince the WHO officials that certain infections could be airborne. In December 2019, similar research carried out by Yuguo Li reached her desk. An indoor-air researcher at the University of Hong Kong, Li was among the firsts to discover the SARS outbreak in 2003. His investigation of an outbreak at the Amoy Gardens apartment complex provided the strongest evidence that a coronavirus could be airborne. Like Marr, he too struggled to convince the public health community that their risk calculus was off. Eventually, he decided to work out the math.
The simulations worked out by Li showed that when a person coughed or sneezed, the heavy droplets were too few, and the targets. i.e., an open mouth, nostrils, eyes were too small to account for many infections. Therefore, Li’s team concluded that the public health establishment had got it backward and that most colds, flu, and other respiratory illnesses must spread through aerosols instead. The latest findings had exposed the fallacy of the 5-micron boundary.
He went a step further, tracing the number back to a decades-old document the CDC had published for hospitals. The new findings brought excitement to Marr. Co-incidentally, a journal asked her to review Li’s paper, and she did not have any hesitation about that. On January 22, 2020, she wrote, “This work is hugely important in challenging the existing dogma about how infectious disease is transmitted in droplets and aerosols.”
A day later, the Chinese government officially stopped traveling in and out of the city of Wuhan in a desperate attempt to contain an as-yet-unnamed respiratory disease that had bought an 11-million-populated city into its knees. As the pandemic shut down country after country, the WHO and the CDC insisted that the infection was not a serious one and asked them to people to wash their hands, scrub surfaces, and maintain social distance. They did not utter anything about masks or the dangers of being indoors.
A 60-year-old study caused WHO to commit its greatest blunder
A few days later, Marr got an email from another aerosol scientist and an atmospheric chemist at the University of Colorado Boulder named Jose-Luis Jimenez. Jimenez, like Marr, was fixated on the WHO recommendation that people stay 3 to 6 feet apart from one another. According to Jiminez, the social distancing guideline seemed to be based on obsolete studies from the 1930s and 40s. Interestingly, the authors of these guidelines had themselves not ruled out the possibility of airborne transmission, which by definition would involve distances over 6 feet.
Strangely, nobody understood the reluctance of WHO not to consider the possibility of the Wuhan virus being airborne. Marr apprised Jimizez about her concerns with the 5-micron boundary and suggested that their two issues might be linked. If WHO based its 6-foot guideline on an incorrect definition of droplets, the 5-micron error was not just some misjudgment. For them, it seemed that WHO and CDC were deliberately sitting on flawed guidance. The scientists had a new purpose now – to find the origin of such distorted research.
With the help of Tom Ewing, a Virginia Tech scholar, and Katie Randall, Marr and the team began to dig for the citations that had become the basis of the ‘5-micron’ theory to consider infection as airborne or not. As they looked deeper, they found a research paper written in 1934 by a Harvard engineer named William Firth Wells Wells and his wife, Mildred Weeks Wells, a physician. The couple had analyzed air samples and plotted a curve showing how the opposing forces of gravity and evaporation acted on respiratory particles. The couple’s calculations made it possible to predict when it would take a particle of a given size to travel from someone’s mouth to the ground.
According to them, any particles bigger than 100 microns sank within seconds, and smaller particles stayed in the air. Randall paused at the curve the wife-husband had drawn, where she discovered the root of the idea of a droplet-aerosol dichotomy. However, the only exception in the graph was that it read around 100 microns, not 5. Years later, the scientists inside the CDC conflated the couple’s observations and plucked the size of particles out of context, based on the data of tuberculosis, to generalize the particle size to 5 microns. So, CDC kept a static guideline to classify whether an infection was airborne or not.
“Wells’ 100-micron threshold got left behind. You can see that the idea of what is respirable, what stays airborne, and what is infectious are all being flattened into this 5-micron phenomenon,” Marr and her team noted. Over time, this flawed understand became the norm to classify infections and pandemics.
Marr did not stop there. They wanted to get to the bottom of the 5-micron myth and dislodge it from decades of public health doctrine. To do this, she had a massive task at hand – to convince two of the world’s most powerful health authorities – WHO and CDC. Marr and her team had to convince these two organizations not only that they were wrong but that the error had caused irreparable damages. More than it, the error was urgent and consequential as Wuhan coronavirus had begun to wreak havoc.
Scientists publish their research, WHO owns its mistakes after a year and 3.3 million deaths
In July, Marr and Jimenez went public about their research, started a signature campaign with an open letter addressed to public health authorities, including the WHO. More than 237 other scientists and physicians warned that WHO should make stronger recommendations for masking and ventilation, failing which the airborne spread of SARS-CoV-2 would undermine even the most vigorous testing, tracing, and social distancing efforts.
The campaign went viral, inviting a strong backlash from a section of public health personalities, who rushed to defend the WHO. However, realizing its error, days later, WHO released an updated scientific brief acknowledging that aerosols may cause infection through the air, especially in poorly ventilated places. However, it stuck to its social distancing norms, advising people to wear masks indoors only if they could not keep that distance.
Even as WHO officials continued to discredit their research, Marr and Jimenez found ways to educate people about the seriousness of the Wuhan virus and its ability to be airborne. Marr spoke to Kimberly Prather, an atmospheric chemist at UC San Diego, who had the ear of prominent public health leaders within the CDC and on the White House Covid Task Force. In July, both explained the research to Anthony Fauci, director of the National Institutes of Allergy and Infectious Diseases. They showed how the 5-micron theory was flawed and explained the trajectory of a 5-micron particle went farther than 6 feet—hundreds of feet farther, making social distancing redundant.
A few weeks later, Fauci admitted that the 5-micron distinction was wrong and had been for years. “The bottom line is, there is much more aerosol than we thought,” he said. Days later, the CDC updated its guidance to acknowledge that SARS-CoV-2 can spread through long-lingering aerosols.
In December 2020, the WHO also acknowledged more about aerosols. On December 1, WHO finally recommended that everyone always wear a mask indoors wherever Covid-19 is spreading. Rather than acknowledging the massive blunder they had committed, WHO patted themselves, saying the change reflected the organization’s commitment to evolving its guidance when the scientific evidence compels a change. The WHO officials maintained that the WHO had initially paid attention to airborne transmission in hospitals, then at places such as bars and restaurants.
Last month, on Friday, April 30, the WHO quietly updated its page on its website to acknowledge that the coronavirus gets transmitted through the air. The website now states that the virus can spread via aerosols as well as larger droplets. The biggest news of the pandemic, however, passed with no news conference, no big declaration.
Alas, World Health Organisation finally woke up from its deep slumber to recognize that SARS-Covid-19 is an airborne infection, a pandemic that has killed more than 3.4 million people and infected at least 164 million people worldwide.