Jeff G, I know we don’t know, but my read of the available data suggests to me you are much closer to the actual numbers here. The mortality rate elsewhere has looked to be about 1% but even then there was probably an underestimate of the number of people who had been infected but were asymptomatic and recovered, never knowing they had had the disease and so not being included in the statistics. A number of 33m (estimate) who have been infected is quite plausible and is, I feel, much more likley than 3.3m. The mortality rate of about 0.5% also looks reasonable. Given the transmission rate and the still increasing levels of new infections, it seems that the US is likely on the way to having had another 1% of the population infected and there is only little room for optimism in terms of the mortality rate, which may be slighted improved in this cohort with the use of drugs and treatment strategies which have been shown to shorten the disease lifecycle somewhat.

There are a couple of things here that should be of real concern.

1. People say the US is ‘going for herd immunity’. This is usually considered to need 60–70% of the infectable population of get infected and recover: So, c220m American’s.
2. Tens of thousands, perhaps humdreds of thousands will need to be hospitalised, in some cases for months. Without the curve being flattened very quickly, even a country as advanced as the US is likely to run out of ICU beds, ventilators etc
3. There is no solid evidence yet that herd immunity is even possible. The common cold is a virus but we do not develop immunity having been infected, or if we do at all it is only for maybe a few months
4. There is growing evidence that this is not just a respiratory system infection, it is a whole-of-body infection which seems, at least in some patients, to leave lasting damage. How much, how long, how severe? We don’t know yet and are still learning, but many people do not just ‘get over it’
5. The numbers needing hospital care will put pressure on other services so some people will die needlessly or earlier than needed to be the case, not from COVID 19 but from, say, cancer or stroke. Shortage of ICU beds, shortage of overall hospital spare capacity, reluctance of people even to attend hospital because of fears about the virus etc. This means that you have to add the additional deaths in the population only caused indirectly by COVID 19 to the to directly caused mortality to get the overall number.