Since April I’ve been estimating that the covid mortality rate in the US is around 0.6 percent. That number is based on the few systemic random surveys of immunity that have been conducted in this country and elsewhere. Lately I’ve been wondering whether I should revise that estimate downward.
About a month ago the CDC released a study estimating a US mortality rate of 0.3 percent. I questioned that estimate at the time, and the second wave of the CDC’s serology meta-analysis reinforced my skepticism. Still, there are plausible reasons why the mortality rate may have decreased since the early days of the epidemic. Medical care has improved with experience. As I noted in my last post, nursing homes, the source of more than 40 percent of corona deaths, have tightened their safety measures. On the other hand, there isn’t compelling evidence to support the contention that the virus is now infecting relatively younger people who are less likely to die from the infection.
Now here comes a new random serology survey out of Riverside California. Some observations:
Of about 3,500 people contacted, 1,726 people were tested, and 101 tested positive, which is a positivity rate of 5.9 percent. [Principal investigator Dr. Cameron] Kaiser says that means somewhere between 118,000 and 175,000 people have already had the virus, which might give us a better idea of the true fatality rate. “We haven’t finished the data analysis, but I will say most estimates place it somewhere between 0.5 and 1 percent overall, and I’m not seeing anything with our numbers that challenges that,” he said.
So I’m sticking with the 0.6 percent estimate for now.