Dr KK Aggarwal
The WHO on Thursday released new guidelines on the transmission of the novel coronavirus that acknowledge some reports of airborne transmission of the virus that causes COVID-19, ut stopped short of confirming that the virus spreads through the air.
WHOacknowledged that some outbreak reports related to indoor crowded spaces have suggested the possibility of aerosol transmission, such as during choir practice, in restaurants or in fitness classes. (https://bit.ly/2Ck7QBo)
WHOsaid the coronavirus that causes COVID-19 spreads through contact with contaminated surfaces or close contact with infected people who spread the virus through saliva, respiratory secretions or droplets released when an infected person coughs, sneezes, speaks or sings.
People should avoid crowds and ensure good ventilation in buildings, in addition to social distancing, and encourage masks when physical distancing is not possible.
Pandemic is driven by super-spreading events, and that the best explanation for many of those events is aerosol transmission People without symptoms – to wear masks.
Only a very small number of diseases are believed to be spread via aerosols, or tiny floating particles. These include measles and tuberculosis – two highly contagious pathogens that can linger in the air for hours and require extreme precautions to prevent exposure.
WHO is using an “outdated definition of droplets and aerosols” and is too focused on the size of the droplets and the distance they travel. WHO defines aerosols as being under 5 microns because only particles that small could float in the air long enough to be inhaled. However, Linsey Marr, an aerosol expert at Virginia Tech said a much larger range of particle size has been shown to contribute to infection. Rather than size, the differences between droplets and aerosols should be based on how the infection occurs: If a person inhales the virus and becomes infected, it’s an aerosol. If the infection occurs by contact, they are droplets. Although WHO has been focused on airborne transmission at long distances, Marr said breathing in aerosols “is of greater concern at close contact and when people are in the same room. [Reuters]
