How common is asymptomatic COVID-19? How infectious is it? And how much does it actually contribute to overall transmission? Nicola Low spoke on behalf of herself and Muge Cevik to outline the role of asymptomatic transmission. She cited a BMJ news piece, which has been used to imply that the death rate from covid might be lower than we think that it is, because undetected people have somehow been left out of the denominator, and explained that these claims are untrue.

One difficulty when identifying our picture of who is asymptomatic is the fact that everyone who tests positive is initially presymptomatic (i.e. asymptomatic until they subsequently develop symptoms).

Can we identify people who are infectious or not? Jon Deeks spoke about the evidence on the relation of lateral flow tests and infectiousness—a key part of the arguments for testing asymptomatic individuals. He presented a rapid run through of existing evidence and concluded “we can’t really be talking about tests of infectiousness”.

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