Seroprevalence data for TN and some insights.

The seroprevalence data for the second half of March is out. In TN, about a quarter of blood samples (taken for reasons unrelated to covid) have antibodies from infection (not vaccination). This comes out to 1.7 million Tennesseans with these antibodies. The official count on March 31 was about half that.

We don't have all-cause mortality data out to 3/31, but if we add in the excess deaths from 2020 to the official count, we get about 16K deaths in TN. So the estimated fatality rate is just shy of 1% for the total pandemic in TN so far. Infections are skewed toward younger people, so I'm a little surprised that it's that high.

Looking back to the end of 2020, 1.2 million Tennesseans had antibodies, and there were about 12K excess deaths, so that's also about 1%. At least given these admittedly limited data, it doesn't look like the fatality rate is getting worse in TN in recent months.

There is a lot of vaccine hesitancy in TN, especially among older people. Vaccination is skewed somewhat towards older people, but not as much as you'd think. Even for people in their 70s and 80s, fewer than half are fully vaccinated. There are apparently a lot of people getting just one shot of the RNA vaccines, and for older people especially, that's not enough.

The 2020 fatality data included highly vulnerable people like those in nursing homes. Presumably much of the older population there has been vaccinated.

So the fact that the fatality rate for the past month didn't decrease suggests to me that the current strains are more fatal to younger people than were the original strains. Otherwise, the fatality rate should be falling as the vulnerable are vaccinated.

If I do the same calculation on CT, the state with the highest rate of vaccinations right now, I am also not seeing a decrease in the fatality rate, which does suggest that the variants are increasing the fatality rate in younger people there.