Thread by @shashikaLB

As #SriLanka tries to understand airborne transmission of #COVID19 - here is a thread of four key papers published in the @TheLancet & @bmj_latest (I’m sure there are more) to provide answers to what is airborne transmission and how to prevent it. @MoH_SriLanka @HPBSriLanka

First is the Lancet paper by Greenhalgh et al. that provide 10 reasons why airborne transmission is the dominant source of #covid19 transmission. thelancet.com/journals/lance… #COVID19SL #COVID19

Key takeaways in terms of prevention from this paper is to limit indoor gatherings/increase ventilation indoor settings/mask wearing/ prevention efforts of only plastic barriers do not work cz the virus can spread through air via tiny droplets esp. indoor settings. #COVID19SL

Second is this easy to read @bmj_latest article by Chris Baranuik collecting everything we know about airborne transmission so far and it’s public health implications. bmj.com/content/373/bm… #COVID19SL

As we have debated since the onset of #covid19 there’s a definitional challenge of aerosol vs airborne transmission but for the purposes of prevention we can consider the airborne transmission to be present. #COVID19SL

There are two case studies from restaurant in Guangzhou, China, Church in Australia, that show clearly virus spreading way beyond 2 meter limit infecting more. Note the indoor setting in both cases. #COVID19SL

Currently @WHO has stated “Aerosol transmission can occur in specific situations in which procedures that generate aerosols are performed.” This is understandable as WHO need to be 💯sure b4 confirming - however we can look to public health prevention implications #COVID19SL

Prevention: “includes ventilation—such as opening windows—and avoiding enclosed spaces. Japan puts emphasis on avoiding the “3Cs”: crowded places, close contact, close conversations—this is echoed in WHO communications that emphasise location, proximity, and time.” #COVID19SL

Paper states wearing N95 masks is better than others, outdoor crowded spaces still risky and indoor spaces has highest risk. It’s better to be masked as much as possible. #COVID19SL

If you want to delve deeper into the definitions of airborne transmissions vs aerosol transmission read this by Tang et al. bmj.com/content/373/bm… #COVID19SL

Key message: improving indoor air ventilation and masking w/ high filtration is better (N95) #COVID19 #COVID19SL

This editorial by Wilson et al. from August 2020 argues that we really need to consider prevention efforts for airborne transmission. #COVID19 #COVID19SL bmj.com/content/370/bm…

The key takeaway from this editorial is the ‘how’ of #COVID19 aerosol/airborne transmission “It is wrong to assume that droplets land only on exposed mucosal surfaces such as the eyes and mouth.” #COVID19LK #COVID19SL

“Particles up to 50 µm can be captured by inspiratory airflows and are deposited along the much more extensive surface area of the respiratory tract;”

“particles below 10 µm can penetrate as far as alveoli. The site of deposition may determine the viral dose required and severity of respiratory infection, as observed in influenza.”

Overall, increasingly evidence has shown (despite definitional challenges) for practical purposes airborne transmission of #COVID19 should be considered present and thus prevented

with a highly infectious strain #SriLanka should to follow limit indoor gathering / improve indoor ventilation/ limiting outdoor gathering / wearing high filtrations masks. The case for it is made via the 4 papers above. We can be safe by being aware and vigilant. #COVID19SL

If you are a company, organization I would consider limiting your indoor gatherings/workshops; at a personal level we all should follow public health guidance; govt. can improve messaging and go for stronger measures of restrictions. #COVID19SL #COVID19LK #COVID19 #lka #SriLanka