A recent article in The New York Times reported that 239 scientists from 32 countries have authored an open letter to the World Health Organization (WHO), concerning the potential for COVID-19 viral particles to remain airborne for a prolonged period of time. The scientists “outlined the evidence showing that smaller particles can infect people, and are calling for the agency to revise its recommendation.”
COVID-19 – the disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), often simply referred to as the coronavirus – is transmitted person to person via airborne droplets. These are created when an infected individual coughs or sneezes, sending viral particles into the air within mucus. The key differentiation is the size of these droplets. Droplets that are five to ten microns in diameter are referred to as respiratory droplets. While technically airborne, these droplets are comparatively large and eventually succumb to gravity, typically falling to the ground within a distance of around a metre.
Droplets categorised as airborne are those that are below five microns. These are referred to as droplet nuclei. These airborne droplets can travel further than one metre, as well as remain suspended in the air for prolonged periods of time. This is of considerable concern in the case of COVID-19, as even physical distancing measures may only have a limited effect if airborne transmission is occurring.
Studies have already found that SARS-CoV-2 can remain viable in aerosols for a period of several hours. In theory, this could allow the virus to still remain transmittable even after a prolonged period drifting in airborne droplets. However, the World Health Organization (WHO) has thus far disputed the possibility, claiming that “…the finding of COVID-19 virus in aerosol particles up to three hours does not reflect a clinical setting in which aerosol-generating procedures are performed — that is, this was an experimentally induced aerosol-generating procedure.”
The possibility that COVID-19 transmission could potentially be airborne highlights the need for the use of protective face masks. If the claim is true, physical distancing measures will have a very limited effect and far more caution must be taken.
Figures in India are now swiftly approaching 800,000, with numbers exceeding 20,000 new cases per day now being the new norm. Weeks of ever-increasing daily figures have seen India climb the ranks of the most-affected nations in just a short period of time. India is now ranked global third for total COVID-19 cases, only surpassed by the US and Brazil. Given the speed of India’s increase in daily cases, coupled with its vast population, India’s disease figures could plausibly increase beyond even that of the US in the coming months.