It took WHO two years to finally admit that the new coronavirus can be 'airborne'

As 2021 draws to a close, the highly contagious Omicron variant of the pandemic virus is competing globally, forcing governments to take another drastic action

On December 23, the World Health Organization finally acknowledged a word it previously seemed unable to use for the SARS-CoV-2 virus: "airborne

On its website, a page titled "COVID-19: How It Spreads" has been quietly edited to say: "When airborne infectious particulate matter is inhaled over short distances, a person may can become infected, a process also known as 'short-range aerosol or short-range airborne transmission

"It's a relief to see that they finally use the term 'airborne' and make it clear that airborne and aerosolborne are synonymous," said Jose-Luis Jimenez, an aerosol chemist at the University of Colorado Boulder.

The seemingly uncontroversial statement marked a clear shift from the Switzerland-based WHO, which had tweeted early in the pandemic: "FACT: #COVID-19 is NOT airborne

It wasn't until October 20, 2020 that the WHO acknowledged that aerosols - tiny liquids - could transmit the virus, but the WHO said it was a concern only in certain settings, such as indoors, crowded and poorly ventilated spaces

But this latest adjustment is the WHO's clearest statement yet on airborne transmission of SARS-CoV-2

The change aligns the WHO's message with what aerosol and public health experts have been trying to align since the early days of the outbreak

Lidia Morawska, an aerosol scientist at the Queensland University of Technology in Brisbane, Australia, has spearheaded several efforts to convince the World Health Organization (WHO) and other health agencies of this.

Critics say the agency's inaction has caused national and local health agencies around the world to be similarly slow to respond to the airborne threat

The tense atmosphere at the beginning of the epidemic

In the final days of March 2020, Morawska reached out to dozens of colleagues—aerosol scientists, infectious disease experts, construction and ventilation engineers from around the world—to educate the outside world about the airborne threat of SARS-CoV-2

Within an hour, the CIA called

Morawska makes a compelling case for airborne transmission

She and others who study aerosols and airborne diseases say the international infection and control team is ill-equipped to assess such transmissions because most of its members are focused on controlling infections in hospitals and they lack how airborne infectious diseases spread expertise in physics

"If it's a new disease, you'd better include everyone," said Yuguo Li, a built environment engineer at the University of Hong Kong,

Marcel Loomans, an indoor air quality physicist at Eindhoven University of Technology in the Netherlands, says it's often difficult to find common ground between the two disciplines

This disconnect exists even in the use of scientific terms
.
Infection control experts have long distinguished between droplet viruses and airborne viruses, arguing that only the latter can travel far and linger in the air
.

"We took the questions they raised at the meeting very seriously, and we responded,
" said Schwaber, who chairs the IPC GDG at the World Health Organization's April 1 meeting.
He said there was evidence at the time that hospitals Airborne precautions - including N95 masks for staff, visitors and patients - are not necessary
.
Still, in the face of soaring deaths among frontline doctors and nurses, most hospitals and health facilities have adopted these precautions in their COVID-19 wards, along with less stringent protections like wearing surgical masks in other areas of the hospital
.

“It’s largely arbitrary bias,” said Don Milton, an occupational health physician who studies the aerosol transmission of infectious diseases at the University of Maryland in College Park
.

Mark Sobsey, an environmental microbiologist at the University of North Carolina at Chapel Hill who is a member of the IPC GDG, said that, especially in the early days, concerns raised to the WHO about airborne transmission were "basically none.
based on” and lack of credible evidence, such as the isolation of infectious virus particles from air samples
.
Epidemiological data from outbreak investigations are "particularly weak," he said
.

In August 2022, IPC GDG members including Schwaber published a review article in which the authors dismissed studies using airflow models, case reports describing possible airborne transmission, and summaries of airborne evidence, and referred to these reports as "opinion sheets".
"
.
Instead, they concluded that "SARS-CoV-2 does not spread to any significant degree via airborne routes"
.

Throughout 2020, there was also growing evidence that indoor environments pose a much greater risk of infection than outdoor environments
.
An analysis of outbreak records reported through mid-August 2020 shows that people are more than 18 times more likely to be infected indoors than outdoors
.
Such a large difference would not have been observed if heavy droplets or dirty hands were the main vectors for spreading the virus
.

While the WHO played down the risk of airborne transmission, it did invite Dr Li, a built environment engineer, to join the international infection and control team after he spoke to the group in mid-2020
.
He said that if the group hadn't at least been open to his view that the infection was caused by aerosols, especially at close range, "they wouldn't have invited me there because they knew my situation.
"
.

Still, Dr Li was disappointed that the WHO did not acknowledge a role for aerosols in community transmission of the disease until October 2020
.
In its December 2020 update to its guidelines for mask use, the agency still highlighted gaps and gaps in the evidence of aerosol transmission, and the need for more "high-quality research" to understand the details of how the virus spreads
.
A question-and-answer section on how the virus spreads on the agency's website did not add remote aerosol transmission until the end of April 2021
.
The term airborne will not be officially added until December 2021
.

conservative approach

Some scientists have pointed out that the WHO's decision to classify SARS-CoV-2 as airborne is a bit late but significant
.
That's because it contradicts the established view of respiratory virus transmission, which was prevalent at the start of the pandemic, that nearly all infectious diseases are spread through droplets, not the air
.
The researchers say the change is particularly important because the group typically takes a conservative approach
.

COVID-19 rarely spreads through surfaces
.
So why are we still doing deep cleaning?

hard line

May Chu, a virologist who is a member of the IPC GDG at the Colorado School of Public Health in Aurora, said the WHO took a hard line, often being fairly conservative in its recommendations, to avoid releasing information that later turned out to be incorrect
.
"You can't go back on advice," Fisher added, because "then you're completely discredited
.
"

Sandman's partner Jody Lanard said the gravity of the situation could make the WHO more cautious in its statement and less likely to deviate from consensus
.
Jody Lanard is an independent risk communication specialist who has also worked with WHO in the past
.

In past situations, such as during the Ebola outbreak in West Africa, and in the polio vaccine campaign, the WHO has been more flexible than during the COVID-19 pandemic, Lanard said
.
"I see them being able to change their approach, or try something different," she said
.
But during a pandemic, "it's easy for people to be very, very cautious" because the agency's advice will affect millions of lives
.
When there is growing concern that SARS-CoV-2 could be airborne, why is WHO not taking precautions and acknowledging the possibility of different risks, even in the absence of hard evidence
.

"They're not entirely wrong, either," Li said of those who claimed there were loopholes in the evidence for airborne transmission, especially over long distances
.
"Looking for solid scientific evidence isn't a bad thing," he said, but "are you still waiting for a good Nature or Science article when you see this spread so dramatically?"

Despite the uncertainty, other health groups are moving faster than the WHO
.
In February 2020, the Chinese Center for Disease Control and Prevention contacted Dr.
Li for advice on air conditioning in public buildings and public transportation
.
On Li's advice, he said, the center suggested maximizing airflow from the outside of the building to help clear any airborne contagion
.
At the time, Dr Li only suspected that the virus could only be spread through the air over short distances, but he didn't think ventilation would drastically reduce infection -- a hypothesis he later disproved
.
But he suggested improving ventilation because "I've always supported preventive measures," he said
.

On the science side, questions remain about how much of the spread of COVID-19 is airborne
.
Researchers still need to find evidence that this airborne route "makes a significant contribution to the overall disease burden," Sobsey said
.
Many on the other side, like Jimenez, believe that airborne transmission is dominant
.
On March 23, the Office of Science and Technology Policy strongly supported this view, with its director, Alondra Nelson, in a report titled "Let's Eliminate the Air of Covid-19".
Pollution” statement, which reads: “The most common way COVID-19 spreads from one person to another is when tiny airborne particles of the virus hang in the air after an infected person has been in indoor air for minutes or hours.
indoors
.
"

Other viruses long suspected to be airborne -- including flu and common cold viruses -- will also be scrutinized
.
In September 2021, the National Institutes of Health awarded millions of dollars for a trial to determine whether influenza infection is caused by airborne or droplet transmission
.

Dr Li said that due to the COVID-19 pandemic, awareness of airborne transmission has greatly increased, and research in the next few years may show that most respiratory viruses can be transmitted this way
.
Therefore, when an old or new infectious disease begins to spread, the entire world will be more alert to the possibility of airborne threats
.

According to Sobsey, the attitude of the World Health Organization has also shifted
.
"I think the WHO's thinking has changed dramatically because of the experience with this virus, which is -- even if you're not sure, be more preventive,
" he said.