1/x On Friday I tweeted about a “huge” WHO update, but I didn’t feel it was pitched right, and I wanted to clarify & be more accurate https://twitter.com/HuffmanLabDU/status/1322199388937089024

2/x Releasing a video to promote clear, simple ventilation recommendations is indeed very important. Details can be nuanced, but the general guidance to ventilate to remove airborne particles (aerosols) that can contain SARS-CoV-2 is a critical piece. https://twitter.com/DavidElfstrom/status/1323069645767757824

3/x As several pointed out, this was also not the first time the @WHO has mentioned ventilation.

4/x For example, this @WHO page posted July 29 lists ventilation guidelines for COVID-19 prevention. The page also does not use any of the words: airborne, particles, droplet, aerosol, or inhale; so the reasoning for ventilation is a bit confusing. https://www.who.int/news-room/q-a-detail/coronavirus-disease-covid-19-ventilation-and-air-conditioning-in-public-spaces-and-buildings

5/x The @WHO recommendations have been a bit confusing, in part, because they have said statements on both sides of this discussion while not retracting or clarifying dangerously incorrect statements ( #misinformation) like this from March 28. https://twitter.com/WHO/status/1243972193169616898

6/x To remind myself about @WHO statements on COVID prevention, I also went back to look. Their “advice for the public” from Oct. 13 recommends to avoid “inadequately ventilated spaces” where “respiratory droplets or aerosols” spread more efficiently. https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public

7/x The latest scientific brief on SARS-CoV-2 transmission by @WHO (July 9) brings up the idea of airborne transmission, but makes no clear statement on the importance & adds hedging to make clear they don’t yet think airborne spread is important. https://www.who.int/news-room/commentaries/detail/transmission-of-sars-cov-2-implications-for-infection-prevention-precautions

8/x These are some examples of statements from that WHO scientific brief (July 9) that mentions indoor airborne/aerosol spread of SARS-CoV-2, but then talks about these ideas mostly as hypotheses without support.

9/x Strong statements against the possibility of airborne spread (March 28), tentative steps to hint it could be possible (latest sci brief, July 9), and clearer statements that ventilation is important (e.g. Oct. 13) show the @WHO is making slow progress towards consistency.

10/x Most importantly, I’m glad for public health that @WHO is pushing ventilation, and hopefully they can eventually bring themselves to also explain that this means SARS-CoV-2 can be in the air. Otherwise, ventilating is meaningless. The more clarity of reasoning, the better.

11/x While I was thinking about this today I also saw, to be expected, that @jljcolorado wrote a good thread on this topic today, worth reading: https://twitter.com/jljcolorado/status/1323279393725194240