I've seen a claim making the rounds today that a Japanese study found incredibly high rates of COVID antibodies in a group of people where no one got seriously ill, and therefore that we don't need precautions. A few thoughts threaded:

One, it's a preprint and hasn't peer-reviewed. So not exactly gospel yet. https://www.medrxiv.org/content/10.1101/2020.09.21.20198796v1.full.pdf

Two, it looks at people commuting to various locations of one company in Tokyo. So not a generalizable sample, since the oldest participant was 69.

Three, they excluded people who developed symptoms, because the goal was to study asymptomatic people. That's fine. But it doesn't mean half of Japan got the virus and never noticed.

Four, it's great that 152 employees of this particular Japanese company didn't get sick despite being infected. That doesn't change that there are 200,000 Americans dead from COVID-19. End of thread.