Next in line for interpretation by @biobook
https://m.twitter.com/EricTopol/status/1270178612457598976
https://m.twitter.com/kevinpurcell/status/1270834406983217152
https://m.twitter.com/EricTopol/status/1270835652662161409
@Dan, Finished my homework:
Recently, van Kerkhove of WHO said that asymptomatic people rarely transmit COVID-19 (though she rescinded that the next day ). Eric Topol tweets to remind us that this is not true.
He mentioned one paper (Nature Medicine, April 15) that showed that an infected person can shed viral particles 2-3 days before they get sick.
Kevin Purcell tweeted that we’re not sure if those viral particles are infectious, but Topol responded that another recent paper showed that in at least 17% of those with severe symptoms, viral particles are infectious, generally for 8 days, but could be as long as 15 or 20 days.
Topol further referred to his own review of 16 studies done thus far on asymptomatic people. The most informative was one from northern Italy where everyone in a small town was tested and found that 45% were asymptomatic, and remained asymptomatic 2 weeks later. Finally, they did extensive contact tracing, and showed that at least some of these asymptomatic people were able to infect others.
Others of the 16 studies confirmed this, finding 40% of a population being asymptomatic, and showing that at least some of these people can infect others.
In addition, they mentioned that seemingly asymptomatic people can actually have internal symptoms, such as lung damage discovered in several. It’s not known how common or serious this might be.
Also unknown is just how often transmission occurs from the asymptomatic to the healthy. Considering the large number of asymptomatics, it’s critical that we figure this out, and Topol tweets the need for contact tracing, to figure out where a patient might have been infected and who he might transmit the infection to and repeated testing to see how long the viral particles remain infectious.
All this can take time, and so in the immediate future, we should treat everyone as if they’re an asymptomatic carrier and can infect others. The best way we know right now to decease the risk of infection is to wear masks.