Caseloads continue to decline as vaccination infrastructure ramps up.

I’m excited that America’s vaccination infrastructure appears to be winning the race with B117 & co, at least for now. At this point the majority of new US cases are from B117 and the other more infectious variants [1], but caseload is still going down in most parts of the country. This is really exciting. I’m glad we’re at a point where we can now distribute excess vaccines to other parts of the world that are struggling.

Field data from Israel show that people who are a week after their second mRNA shot have roughly a 90% reduced risk of catching or transmitting COVID. [2] Israel is also a couple of months ahead of us in vaccinations, and their new case rates have gone down to minimal levels. That’s going to be America in the near future, as long as people keep getting vaccinated.

As a fully vaccinated person in SF, almost every outdoor activity is minimal risk. There have been articles questioning whether we should keep wearing masks outdoors. I generally agree with them, at least in SF’s case. Based on the numbers in SF, I think it’s fine to stop wearing masks outdoors unless you’re in a large and dense crowd.

Formerly high risk activities like indoor dining are now moderate risk – one indoor meal at full table density is about 30% of your weekly risk budget if you’re aiming for a 1% per year chance of catching COVID. In reality, it’s probably lower than that as restaurants are forced to limit indoor capacity.

Small and medium indoor gatherings of fully vaccinated individuals are quite safe. For example, a fully vaccinated 10-person 3 hour indoor unmasked gathering where people are relatively close together but not cuddling is about 15% of your weekly risk budget if you’re aiming for a 1% annual risk of catching COVID. [3] This number will vary somewhat across the country, but not by that much, as most states are vaccinating at roughly similar rates.

We’re not quite at the point where fully vaccinated people can pack closets like sardines or throw massive indoor parties, but we’re well on the way. Hopefully caseload will continue to drop over the next month to the point that you’ll be able to fulfil your wildest dreams of breathing on lots of other humans.

Furthermore, based on an informal survey of friends, it appears that everyone I know in SF has had their first shot already, so you should be able to hold indoor events by June 1, require full vaccination of entrants, and not exclude anyone.

[1] https://covid.cdc.gov/covid-data-tracker
[2] https://pubmed.ncbi.nlm.nih.gov/33626250/
[3] In SF, if we assume ~25% are fully vaccinated + 1 week and another ~25% are 2 weeks past their first shot, and consider the number of J&J vaccinations to be negligible, a fully vaccinated individual has a roughly 6x lower chance of having COVID than a random person who may or may not be vaccinated. (The rough math for this is (0.51 + 0.250.56 + 0.25*0.1) / 0.1 = 6.65x risk reduction.) I’m rounding down to be on the conservative side.