Thread by @DrEricDing

📍Wasted $750 million on #COVID19 plexiglass instead of air quality. ➡️ “We spent a lot of time & money focused on hygiene theater. Danger is we didn’t address the real threat—airborne transmission—real $, time & attention.” @j_g_allen. #COVIDisAirborne
bloomberg.com/news/articles/…

2) Not a single study has shown that the clear plastic barriers actually control the virus, said Joseph Allen of the Harvard T.H. Chan School of Public Health.

3) For the first months of Covid-19, top health authorities pointed to larger droplets as the key transmission culprits, despite a chorus of protests from researchers. Tinier floating droplets can also spread the virus, they warned, meaning plastic shields can’t stop them.

4) Not until last month did the World Health Organization and U.S. Centers for Disease Control and Prevention fully affirm airborne transmission.
That meant plastic shielding had created “a false sense of security,” said @marwa_zaatari, pandemic task force member of @ashraenews

5) “Especially when we use it in offices or in schools specifically, plexiglass does not help,” @marwa_zaatari said. “If you have plexiglass, you’re still breathing the same shared air of another person.” ⚠️

6) Recent CDC research found that desk or table barriers in Georgia elementary schools didn’t correlate with lower infection rates. Mask mandates and ventilation improvements did.

cdc.gov/mmwr/volumes/7…

7) An April study published by the journal Science suggested that desk shields might even slightly raise the risk of Covid-like symptoms. science.sciencemag.org/content/372/65…

8) And a prepublication paper from Japan late last month linked plastic shielding with infections in a poorly ventilated office. medrxiv.org/content/10.110…

9) Such studies raise the ironic possibility that too much plastic and impede ventilation, they could be raising the very risk they’re trying to reduce.

“Until we recognise that #COVID19 is airborne we are setting ourselves up for repeated failure”

10) How is aerosol different from large droplets? aerosol study indicates that coronavirus is persistent and stable for many hours. Typical air exchange every 20 min to 4 hrs, depending on ventilation. #COVID19

11) VENTILATION is key. Both ventilation and masks needed to reduce risk indoors. But most buildings not ventilated well enough.

12) Now that aerosol transmission of the coronavirus is established, we need to disperse aerosols quickly. Key is ventilation. 🇯🇵 assumed it was airborne from the beginning. Here is how to ventilate your school classrooms if unable to open window. #COVID19

13) The CDC recommends a combination of ventilation + air cleaning in schools in addition to masks. Learn more about the details of what air cleaners are good (and bad) ⬇️

https://twitter.com/drericding/status/1365678603212648461

14) for mechanical air filters (in your HVAC) system, experts recommend MERV 13 rating for air filters that offer 89.9% efficiency. But Merv 13 can also be achieved via a combination of a lower grade MERV + portal HEPA or UV. Source @marwa_zaatari