Thread by @EricTopol

Unfortunately, as an outgrowth of a @WHO statement and @CNBC coverage today there is still significant confusion about the asymptomatic story. Conflation with pre-symptomatic status.
Let's first define these 2 groups

There is ample evidence that presymptomatic people commonly infect others, like this one @NatureMedicine
nature.com/articles/s4159… by @gmleunghku and @hkumed colleagues

Our @AnnalsofIM paper zoomed in on 16 cohorts to partition the presymptomatics vs asymptomatics, which was done by serial assessment in many of these reports
acpjournals.org/doi/10.7326/M2…
and making a conservative estimate that ~40-45% of infected people don't (ever) develop symptoms

But the whether the people in this asymptomatic category (Asx) spread like those who have symptoms (or pre-symptomatics) is not determined. We only know the viral loads are similar from multiple reports. And we do know some spread occurs from ASx people.

To provide meaningful data on the magnitude of transmissibility from asymptomatic people a prospective study would need to be done to quantify spread & ideally include:
—contact tracing, forward and backward
—culture of the virus
—virus genomic sequence to precisely define route

The rest of the relevant points were addressed in a recent thread

https://twitter.com/EricTopol/status/1269359663591510016