> The "70%" herd immunity number is something someone pulled out of their ass in the early days. Recent studies show widespread T-cell immunity, and together wi

> The "70%" herd immunity number is something someone pulled out of their ass in the early days. Recent studies show widespread T-cell immunity, and together with how a virus infection selects people for immunity (it's not the same distribution as a vaccine campaign), it seems that when 10-20% of the population has had it, that's enough for very strong community resistance, causing the virus to die out. Granted, the 70% number is based on an R0 of 3.5 and homogeneous transmission. It's probably lower than that in many cases. In some cases it like prisons or close contact workplaces or other close contact activities it's going to be even higher as some incidents show. The T-cell immunity is something we don't understand very well yet. I hope that only 20% of the population will be enough to stop it, i really do, but right now i don't think it's very likely. We may have the first solid data points after the winter. Yes, we get better at treatment and protective measures. As long as the hospitals are not overrun this may lower the fatalities a great deal. In Sweden it's looking quite good right now. In some areas in the US not so much for the coming weeks. When the hospitals are overrun, you can't help much and the fatalities will increase a lot. Until next summer I will not judge which strategy works best. But I'd rather err on the safe side health wise and advocate for stronger protective measures even if it may mean a higher economic cost (that won't crash the economy completely). If we err on the wrong side, we could lose both, health and economy at the same time. After the numbers are in, we can say with hindsight what would have been the best course of action.