Thread by @Telegraph

🦠After nearly two years of scientific endeavour, which has given us multiple vaccines and drugs to fight coronavirus - we’re still not completely sure how Covid spreads or how to stop it

🧵👇
telegraph.co.uk/news/2021/08/0…

One of the biggest arguments between scientists is whether the virus is truly airborne.

⚖️Understanding how and why the virus spreads is crucial for determining which control measures are effective at breaking the chain of transmission, and which are needlessly disruptive

🌬️Airborne transmission

The case for airborne transmission comes from observational evidence which shows that people confined to closed environments have inexplicably become infected.

Experts also point to super-spreader events that have produced multiple infections

⁉️Why are some scientists still sceptical?

The problem lies in the quality of evidence.

A review by the University of Oxford and funded by WHO found that of the 67 studies looking at the role of airborne transmission, all were of low quality
telegraph.co.uk/news/2021/08/0…

❌“The whole field is plagued by poor quality studies, by ideology-driven sweeping statements that cannot be backed up by science,” said Professor Tom Jefferson, of Oxford University, one of the authors on the review.

“How does it transmit? Most likely droplets and contact”

🚫The case against airborne transmission

No study has found viable viral particles in the air that could have gone on to infect someone.

Professor Heneghan, of Oxford university said: “Nobody has managed to capture a viable virus because once it’s in the environment”

Another problem with the airborne theory is that it has not been proven that humans infected with Covid can generate infectious aerosols of less than 5 micrometres just by speaking or coughing.

❌Although experimental models suggest it could happen, nobody has shown it has

Although lab studies have shown Covid can linger in the air, real-world studies have yet to show airborne virus.

🚂A study by Imperial College and Network Rail, sampled air from stations during the peak of the winter wave, and again in June, found no evidence of the virus

📝Additional problems with the theory

Michael Klompas, Professor of Population Medicine at Harvard University, pointed out that the natural R number for Covid (2.5) should be higher if it was spread through the air, closer to the 18 of measles
telegraph.co.uk/news/2021/08/0…

👉Like airborne transmission, there are no studies that directly demonstrate fomite transmission for Covid; however, other coronaviruses and respiratory viruses are known to transmit through surface spread

😷If the virus is not airborne, then wearing masks is unlikely to do much good outdoors, in ventilated areas or where people are not in close contact with other people

🦠Ecology

Prof Jefferson said even now we know very little about the ecology of this virus.

“The only thing the virus seems to obey is Farr’s Law...

“I am not convinced the path of the pandemic has much to do with our interventions”
telegraph.co.uk/news/2021/08/0…

⁉️The world may have multiple vaccines and drugs to fight coronavirus but we’re still not really sure about how it transmits or how to stop it.

Read more: telegraph.co.uk/news/2021/08/0…