COVID back in the day
a meta analysis of infection fatality rates; revisiting East Asia exceptionalism
Across 31 systematically identified national seroprevalence studies in the pre-vaccination era, the median infection fatality rate of COVID-19 was estimated to be 0.035% for people aged 0-59 years people and 0.095% for those aged 0-69 years.
*The median IFR was 0.0003% at 0-19 years, 0.003% at 20-29 years, 0.011% at 30-39 years, 0.035% at 40-49 years, 0.129% at 50-59 years, and 0.501% at 60-69 years.
*At a global level, pre-vaccination IFR may have been as low as 0.03% and 0.07% for 0-59 and 0-69 year old people, respectively.
Pointer from Don Boudreaux. My emphasis.
Suppose that the infection fatality rate for age 60-69 is the median of 0.5 percent, or 5 in one thousand. There are about 35 million Americans in that age range when COVID hit. If all had become infected, then 175,000 would have died. That is a lot of folks.
My next door neighbor, who was my age, died from COVID early in the pandemic. That made it quite real for me. We each had three daughters. When my daughters were married, I was present (so was he, for that matter). But he was no longer alive for his two youngest daughters’ weddings.
It seems plausible to me that social distancing and then the vaccine saved thousands of lives in my age bracket. So you can argue that anti-COVID measures had costs that exceeded the benefits, but the benefits were not zero. There was a lot of stupidity: outdoor masking; vaccinating children; closing schools. But the idea that the optimal policy regarding COVID was to blow it off will not get my endorsement.
Separately, Boudreaux points to a paper by Jay Bhattacharya, Phillip Magness, and Martin Kulldorff, which says
The relatively low COVID-19 prevalence in East Asia in 2020 is a genuine puzzle needing an explanation. Of the explanations we have considered, lockdowns, genetics, seasonality, and climate are less likely to solve the puzzle. The relatively older demographic composition of some East Asian countries deepens the mystery since COVID-19 is more likely to cause severe disease in older patients. On the other hand, a differential presence of pre-existing protection against SARS-CoV-2 infection – perhaps from prior human coronavirus or SARS 1 infection – is the most likely answer, but questions remain regarding the specific mechanism. Whatever the mechanism turns out to be, it will need to explain the rapid spread of COVID-19 through East Asia, including China, with the arrival of the Omicron variant in 2022.
They admit that their analysis is speculative. They have no direct evidence for the hypothesis that East Asians enjoyed pre-existing immunity that protected them from the early variants of COVID-19 (but not the Omicron variant). They find studies in the literature that provide evidence against alternative hypotheses, leaving pre-existing immunity as the most plausible story. (Read the paper before you make comments promoting mask-wearing or other explanations.)
I would note that I can come up with reasons to be skeptical about the ability of exposure to SARS 1 to be protective against SARS 2. Would the immunity acquired from an exposure in 2003 not have worn off by 2019? Could enough East Asians have acquired immunity to create herd immunity for the population as a whole?
Still, I agree that the East Asian mystery is one that invites investigation. But scientific curiosity is not our health bureaucracy’s strong suit.