We still don’t know how much spread is droplets vs aerosol. It seems like mostly droplets, but maybe some aerosol.
We still don’t know how much spread is by surfaces. We know viral RNA can persist on smooth surfaces like stainless steel and plastic for 48 hours. But we have only detected the virus in those cases by PCR. We do not know if that virus is replication competent.
We don’t know how long people are infectious. Some people have detectable RNA for weeks, but it seems like when people hit a PCR cycle count of 37+ the odds that they are still infectious are “minuscule”.
We don’t know for sure how much transmission is done by pre-symptomatic / asymptomatic people. But we know that at least 1,156 crew on the USS Theodore Roosevelt ended up testing positive. It seems unlikely that someone coughed on all 1,156 of those people.
Do children transmit in the same was as adults. “Data free zone”. We don’t know, but there is a study in progress and we should have an answer soon.
The downstream effects of having kids out of school, for the kids, for parents, for society, are very “deleterious”. There are some areas where the infection rates are so low that we should clearly send the kids back o school. There are some areas where the infection rate is high enough that we have to do something to mitigate risk, which could be…
What is the CFR? It is totally dependent on the number of asymptomatic cases. It is clearly worse than the flu, and clearly no as bad as SARS. It has got to be somewhere around 1%. But it is hard to
What is the best estimate for seroprevalence in the US? NYC is 22%. US is probably a few percent, maybe 3-4%.
Can herd immunity be achieved without a vaccine?