Scientists Believe There's Growing Evidence of Airborne Transmission of COVID-19
Wed, April 21, 2021

Scientists Believe There's Growing Evidence of Airborne Transmission of COVID-19



News about the novel coronavirus is breaking nearly 24-7, keeping us informed of the increasing number of infected people and encouraging us to take safety measures. Every day, experts are continuously reminding people to not be complacent when going out or meeting people because the virus is highly contagious.


How Coronavirus is Spreading

According to researchers, on average, every person who has COVID-19 will pass it on to 2 or 2.5 others. One study found out that the number is even higher, with one sick person infecting 4.7 and 6.6 others. Unfortunately, the only way to know if someone has been infected is to test them because the symptoms of the disease look extremely similar to that of the common cold or flu: fever, cough, and body aches. 

There are also asymptomatic carriers who can harbor the virus without showing any signs and spread it to other people. Thus, many health professionals encourage the public to understand how coronavirus spreads so they can take the right steps to not get sick and infect others. The Centers for Disease Control and Prevention (CDC) reported that COVID-19 is spread mainly from person-to-person, usually via close contact.

Being near an infected person who coughs, sneezes or talks can simply expose other people to their infected respiratory droplets. These people could even contaminate surfaces just by touching them, infecting more people unknowingly. "A sneezing or coughing person will cover their mouth, get it all over their hand, and then touch something that you then touch," Robert Murphy, MD, an infectious disease expert at Northwestern University, said.



A recent study published in the Journal of Hospital Infection found out that the coronavirus can live on surfaces like metal, plastic, or glass for anywhere from two hours to nine days. According to, an online site that delivers accurate, trusted, up-to-date health and medical information for consumers, another research in the New England Journal of Medicine revealed that the virus can live on plastic and stainless steel for two to three days, on cardboard for up to 24 hours, and on copper for up to four hours.

Recently, many scientists revealed that the virus can get transmitted through the air we breathe. Other experts warned that there’s growing evidence of airborne transmission of coronavirus.



Coronavirus is Likely Airborne: WHO

For months, the World Health Organization (WHO) is firm that the coronavirus spreads primarily by large respiratory droplets when they are expelled by infected people in coughs and sneezes. These droplets are then transmitted to other people. David Heymann, a professor of infectious disease epidemiology at the London School of Hygiene and Tropical Medicine and chair of the WHO’s strategic and technical advisory group on infectious hazards, said that there’s little sign they travel far.

“There is limited evidence that aerosols generated by talking, coughing or sneezing can spread more than 1 meter, thus becoming airborne, and there is limited evidence that airborne transmission plays a role in the community spread of COVID-19,” he said.

However, several reports of contact tracing show another conclusion: coronavirus is likely airborne. For instance, a study revealed that coronavirus was spread in a restaurant in China, infecting other customers even if they were six feet or more apart. The researchers said an air conditioner pushed virus-laden air to those people, suggesting that it can travel through the air. Controlled laboratory studies also suggest that COVID-19 can float in the air under the right indoor conditions.




Recently, 239 scientists in 32 countries released an open letter to the WHO, outlining the evidence that shows smaller particles can infect people. They urged the organization to consider that the novel coronavirus is lingering in indoor spaces, dismissing its early notion that airborne transmission was unlikely to occur outside the hospital setting. The authors hope that the WHO’s recognition of this mode of transmission can encourage communities to think more about the ventilation of indoor spaces and perhaps engineer solutions to make these spaces safer.

The WHO’s updated brief noted that there’s been reported outbreaks of COVID-19 in some close settings. This includes restaurants, nightclubs, places of worship or places of work where people maybe shouting, talking, or singing. According to Live Science, a science news website that features groundbreaking developments in science, space, technology, health, the environment, our culture, and history, prior research suggesting that the 2003 SARS epidemic spread through airborne transmission is the strongest evidence for airborne transmission of COVID-19.

"There is every reason to expect that SARS-CoV-2 behaves similarly and that transmission via airborne microdroplets is an important pathway," the scientists said.

The authors also reported a “superspreading” event of COVID-19 that happened at a choir in Washington. They revealed that the recent outbreak infected 53 out of 61 members who attended a weekly choir rehearsal, concluding that airborne microdroplets were the most likely mode of transmission.

"In these events, short-range aerosol transmission, particularly in specific indoor locations, such as crowded and inadequately ventilated spaces over a prolonged period of time with infected persons cannot be ruled out," the WHO said.

Dr. Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, said that while there’s not a lot of evidence about airborne transmission yet, he believes it’s a reasonable assumption that it does occur. This also means that containment measures in indoor spaces should be changed. According to EcoWatch, a leading environmental news site engaging millions of concerned individuals every month, the WHO has already released new guidelines suggesting that people avoid crowds and ensure that buildings are well-ventilated.

"This is a move in the right direction, albeit a small one. It is becoming clear that the pandemic is driven by super-spreading events, and that the best explanation for many of those events is the aerosol transmission," Jose Jimenez, a chemist at the University of Colorado, said.

Scientists also said that with these new findings, masks may be needed indoors, even in socially-distant settings. The ventilation systems in nursing homes, schools, residences, and businesses should also minimize recirculating air and add powerful new filters. Ultraviolet lights may also be needed to kill viral particles floating in tiny droplets indoors.