Thread by @BillHanage

My test Thursday came back negative yesterday evening ~36hrs after the test which is much better than this, but still later than ideal 1/n

https://twitter.com/mlipsitch/status/1327628580252241920

The reason for the test was exposure to a suggestive but non-specific symptom in a member of the household who was also tested 2/n

While waiting for the test result, all members of the household quarantined. Child did not go to school. Prevented any risk of transmission outside the household 3/n

We also wore masks while together, and the symptomatic person slept separately. Common spaces were ventilated - it made the house cold, but that's what warm clothes are for. 4/n

Waiting for the test was a pain, but the result came in relatively quickly. The caveat to this is that as that time increases, the window where you can make any difference to onward transmission narrows 5/n

This afternoon I overheard a parent state that they were planning to get tested weekly. That sounds great, but that sort of approach will flood the system such that people with actual known exposures don't get their results quickly enough to make a difference 6/n

(an anxious worker in a grocery store who wants testing after hearing of symptoms among their colleagues, is not the same as Tarquin's Mum who wants to feel more relaxed after a week of minimal exposures) 7/n

There is a tension here; we want more testing but the people who present for testing may not be those most at risk. We need to ensure equitable access (and response) 8/n

Cases are skyrocketing. Demand for testing is also skyrocketing. I would respectfully suggest that if you have no reason to think you were exposed you might want to hold back and just minimize your contacts 9/n

Negative tests can also lead to a false sense of security. Remember testing negative in the past is not a guarantee for the future. Consider the White House outbreak 10/n

Tests building up in the system can slow the results for the most important tests connected to contact tracing. Once you get beyond a day or so such tests are useless for slowing transmission - the virus has smashed and grabbed and moved on while you're slowly following up 11/n

Did I mention more than 180,000 cases today? Contact tracing is already redundant in many places as the pandemic does its exponential thing. Those where it isn't yet should preserve it. All places should take action to slow transmission 12/n

I said this in the spring and it has served me well dealing with an adversary I only see once it has moved on - however bad you think the situation is, assume it's worse. And then assume it's worse than that for good measure 13/end