As the world continues to fight the COVID-19 pandemic, one question that has come up is whether or not COVID-19 is airborne. Like many issues related to the pandemic, the airborne transmission of COVID-19 is complex. As the virus is relatively new, no one knows the exact answers for sure. However, we at TABIIB would like to shed some light on all the existing research related to COVID-19 airborne transmission.
Airborne Transmission Vs Contact And Droplet Transmission
Before we address the issue of a COVID-19 transmission, let’s look at respiratory infections and the difference between airborne and droplet transmission. Respiratory viruses are transmitted through contaminated respiratory droplets. As per science, respiratory droplets are >5-10 μm in diameter, and anything <5μm in diameter are all droplet nuclei.
Airborne and droplet transmissions are very different from one another. For instance, droplet transmission occurs when a person comes in close contact with respiratory droplets from an infected person directly or indirectly (through surfaces). Due to gravity, these large respiratory droplets don’t remain in the air for prolonged periods of time and they also don’t usually travel a distance greater than 1.5 meters.
In an airborne disease, transmission occurs when droplet nuclei i.e., particles <5μm in diameter, remain in the air for long periods of time, infecting people over distances greater than 1 m.
What’s The Evidence That The Virus Is Airborne?
WHO announced that COVID-19 was a droplet transmitted virus after analyzing over 75,465 COVID-19 cases in China. However, various scientists believe that there is a possibility of COVID-19 being an airborne disease.
When artificially aerosolized, researchers identified that infectious coronavirus particles can persist in the air for at least 3 hours. WHO, however, claims that this study doesn’t indicate the airborne transmission of the virus as the setting used in the study was with a high power machine. This doesn’t reflect the normal human cough conditions.
Recently, 239 scientists from 32 countries also wrote an open letter to WHO arguing and showcasing evidence that the COVID-19 is airborne. Scientists in the open letter to WHO stated that several studies conducted after the SARS-CoV-1 epidemic demonstrated that airborne transmission was the most likely mechanism to explain the spatial pattern of infections. They also raised various instances that point towards the transmission of SARS-CoV-2 through the air.
Despite the open letter, to date, WHO maintains droplet and surface transmission as the main source of infection for COVID-19. In regards to COVID-19 airborne transmission, WHO says that it might be possible only in specific medical circumstances and settings. For instance WHO claims that airborne transmission is only possible in treatments that generate aerosols such as endotracheal intubation, bronchoscopy, open suctioning, manual ventilation before intubation, and so on.
So Is COVID-19 Airborne?
Even though WHO admits that airborne transmission is possible, they claim that they need to further evaluate the current evidence to determine whether it is possible to detect viable SARS-CoV-2 in air samples. To date, WHO stated that COVID-19 is transmitted through droplets or contaminated surfaces. So the best thing to do right now is to follow proper handwashing procedures and physical distancing guidelines.