Thread about the importance of speed in returning #covid19 test results and contact tracing

#Covid19uk #coronavirusuk

The longer the waiting for test results, the less useful those results are for contact tracing

When people (as per current policy in England) get tested after getting symptoms (on average 5 days after getting virus), then they have been already infectious for 2 days on average

During these 2 days they may have transmitted the virus to some contacts. On average it takes 3 days before contacts themselves become infectious. So you have a timeframe of one day to trace those contacts and quarantine them. Same day test results are essential!!

There is a great infographic by @marcelsalathe and @ncasenmare at https://ncase.me/covid-19/?v=3 . I have put in some screenshots below to illustrate the point

This is what happens when you do nothing:

This is the scenarion when people with symptoms self-isolate, but nothing else is done:

And this is the scenario with optimal contact tracing:

And here's the key to the faces: