Thread by @ariehkovler

I think this NYTimes article is too pessimistic. In particular, it doesn't take account of the situation in Israel, where it looks like there *might* be population immunity with just 54% vaccination.

nytimes.com/2021/05/03/hea…

Almost 30% of the population in Israel is under the age of 16. The young population meant that we weren't *expecting* herd immunity here until kids could be vaccinated.

The article suggests that you need 80% vaccination coverage to keep unmitigated R<1. But that doesn't seem to be what we're seeing in real life. Maybe because infected kids alone don't transmit the virus to enough other people to keep the pandemic going?

Cultural venues, restaurants, cafes, bars, weddings etc reopened 8 weeks ago. Some of these businesses are technically limited to 'Green Pass' vaccinated or recovered people, but the rules aren't enforced. I've been asked for my Green Pass exactly once.

This graph from @LittleMoiz shows how hospitalisations are falling. But it's also new infections. Daily new coronavirus cases are down to double-digits, with only one test in five hundred coming back positive.

The US will have more regional effects than tiny Israel. The point @mlipsitch makes here is doubtless correct, though I wonder if his example percentages are too conservative. 70% vaccination among adults is really a lot, plus the remaining 30% will include some recovered people.

Israel's protocol (all Pfizer, 3 week interval between doses) probably also provides a higher level of protection against transmission than the one-dose J&J used in some of the US, at least in the short term.

When I look at case numbers for, say, New York City, I wonder if we're already seeing some vaccine effects there too. Cases falling, test positivity falling. 44% (=54% of adults) had at least one dose.

Yeah, maybe immune escape variants will come, and maybe the high level of immunity conferred by vaccines will wane. But that hasn't happened yet. Right now, I think it's *possible* that much of the US is on the threshold of herd immunity. I guess we'll see.

A few comments noting that Israel still has some indoor masking, case isolation, travel controls and border testing. That's all true (though test positivity of travellers is also about 0.2%).

Of these, I think border controls are the big one. As countries get some level of domestic vaccine-induced immunity, they'll probably still need to prevent large numbers of infected travellers from entering.

I don't really understand why countries, airlines and labs aren't partnering up to offer some sort of universal Covid travel system that includes proof of vaccination or recovery, PCR testing on departure and arrival, and mutual recognition of standards.