The CDC epidemiology study linked below, suggests the R0 for the virus is 5.7 and not 2.2 (each infected person would infect 5.7 others, assuming no interventions/social distancing), as many have thought. I've been quite skeptical of the virus being that transimssible (see the quoted post above). However, the combination of the CDC study, the info I had shared a few days ago, quoted above, suggesting tens of millions (at least 10-20%) could already be infected based on ILI (influenza like illness) rates being abnormally high in Feb thru mid-March (and also the Kisna data on fevers from the internet-connected temperature devices over 1MM have), and what I reported this morning from a NYC doc, suggesting that 30% of NYC could already be infected based on health care worker testing (antibody testing presumably) all do dovetail together. So maybe 20-30% actually infected is where we are now. This is why we need massive antibody testing now to confirm whether this is true.
https://wwwnc.cdc.gov/eid/article/26/7/20-0282_article
If, for argument's sake, 30% of the population has already been infected and is now immune, that's great and horrible at the same time. Presumably, at least, if 30% of the population has already been infected and is now immune, that would mean a fairly large swath of of the population would have immunity to the virus and would no longer be contagious and be able to go back to normal life with no restrictions. That's obviously great, although we need the antibody tests to confirm who those people are. Also, people at low risk of bad infection outcomes should likely be able to go back to work soon, although they'd still need to be careful around high risk folks, since they could still become infected carriers.
I would think some degree of social distancing would be maintained to keep infection levels low - that and 30% already infected should at least mean that any future "spikes" in cases should be significantly smaller, since 30% of the targets are no longer in play. I could imagine seeing a series of spikes over time which continuously diminish in size until we reach herd immunity (where people should no longer be getting infected), which the CDC estimated to be 82% of the population for an R0 of 5.7 (as opposed to 55% for an RO of 2.2.
The R0 values we estimated have important implications for predicting the effects of pharmaceutical and nonpharmaceutical interventions. For example, the threshold for combined vaccine efficacy and herd immunity needed for disease extinction is calculated as 1 – 1/R0. At R0 = 2.2, this threshold is only 55%. But at R0 = 5.7, this threshold rises to 82% (i.e., >82% of the population has to be immune, through either vaccination or prior infection, to achieve herd immunity to stop transmission).
Also, with an R0 of 5.7, this means that at-risk people need to take even stricter social distancing precautions to avoid getting the virus (like we've done for the past 4 weeks - simply no face to face interactions in that whole time). We're able to do that for months until a successful treatment/cure is available or until herd immunity is achieved, whichever comes first, but I understand that not everyone else is, which makes for a difficult public health choice on how far to go with "going back to normal."
There are also the conditions that many (including the gov's of NJ/NY/CT, who have said they'll take a regional approach together) have postulated we'd need to have in place before relaxing social distancing. These include instant viral testing/results so we quickly know when there's a flare-up, antibody testing to see who can safely go back to work/life, and putting much better contact tracing/quarantining systems in place, so we can better prevent spread, especially from asymptomatic/infected contacts.
