Lancet & British Medical Journal (BMJ) on 14th April 2021 – ‘Covid-19 has redefined airborne transmission’.
These two articles compare and explain the meaning and difference between ‘aerosol’ and ‘droplet’ infections and ways to safeguard. Summary is that ‘aerosol’ lingers in the air whereas ‘droplets’ fall to surfaces. For the last one year, it was believed that the COVID-19 virus is spread more from droplet infection hence the stress was on cleaning surfaces where as it is proven now that it is an ‘aerosol infection‘ and spreads more through inhalation hence more stress on ventilation and distance. These articles explain the importance of ‘good ventilation‘ over and above the standard use of masks, sanitisation and social distancing.
An ‘aerosol’ can be best explained by relating it to ‘smoking’. A person sitting closer than 6ft is always referred to as ‘passive’ smoker as he/she is inhaling high levels of smoke. Even if the smoker is wearing a mask or you are, smoke still escapes and spreads in the case of aerosol and you will be able to smell it, meaning you are inhaling it. Some level of aerosol can still be inhaled despite masks and 6ft distance which now explains many cases where people have been extra careful but still got infected. Aerosol virus lingers in the air for hours after the source has moved away. The only way to control this is ‘ventilation’. The air needs to be replaced with fresh air to prevent aerosol infections.
Key suggestions from these articles:
1. Avoid indoor crowded places completely. Outdoors is considered much safer and diffuses aerosol particles.
2. Mask, social distancing and sanitisation is a must in all indoor settings even more.
3. Air ventilation of enclosed areas which sees high movement of people – eg. elevators, lobby, enclosed common areas must have effective ventilation, open doors and/or exhaust fans always on, especially elevators.
4. If an infected person has been in a room, lobby or elevator – apart from regular sanitisation, ventilating the area is just as important. Keep the area / doors / windows / elevator doors open for a while with good ventilation.