My wife and I went to a wedding last week, and 6 of the 14 girls who went to the bachelorette party (all vaccinated) have since tested positive for covid. I and another one of the guys (also vaccinated) got it a few days later, most likely from one of those girls (and not our partners, who both tested negative).
It’s just a few cases, but nonetheless seems hard to square with the lower bound of vaccines still working super well to prevent symptomatic infection.
What kinds of vaccines did you guys have? Also how long ago? I hypothesize a lot of the difference in efficacy reported by the UK (88%) and Israel (64%, kind of close to the efficacy in your situation if we make the generous assumption that all 14 would have been infected without the vaccine) has to do with the fact that Israel started vaccinating earlier.
I got my first shot of Pfizer in September and the second in February. I don’t know the exact answer for everyone else, but at least one J&J and I think mostly mRNA, probably at about the time it became available to 30 year olds in the states.
Any given observation can of course but squared with any given level of effectiveness, because randomness, and also because superspreaders are a thing—so the outcomes can be highly correlated.
Hope no one got seriously ill. From the lack of mention of any adverse effects, I am guessing everyone involved is fine?
Any given observation can of course but squared with any given level of effectiveness, because randomness, and also because superspreaders are a thing—so the outcomes can be highly correlated.
Yeah, depends on what you mean by “hard” exactly, and what your hypotheses are. If the idea is that the vaccine makes 93% of people completely immune and leaves 7% effectively unvaccinated, then getting at least 6 of 14 should be pretty rare—especially if you expect those 7% to be disproportionately old and unhealthy people and the 14 are all fairly young and healthy. Not impossible, but I’m squinting my eyes and double checking the methodology on anything that implies it was “just a fluke”.
Explanations that assume some correlation are easier to buy, but I’m not sure what it could be correlated with that wouldn’t have also shown up enough pre-delta that we’d have heard of some superspreader event where vaccinated people were passing covid to other vaccinated people.
Hope no one got seriously ill. From the lack of mention of any adverse effects, I am guessing everyone involved is fine?
Too early to tell, but I think everyone will be fine. So far no one high risk has gotten sick.
EDIT: I have some more anecdotal evidence. My cousin just told me that his friend has nearly the exact same story with his wife’s bachelorette party. 6⁄15 so far with symptoms and positive tests, all vaccinated. There’s some selection bias there since I likely wouldn’t have heard about it if it were only 1⁄15, but not enough to make it expected under a “just a fluke” model.
Could the fact that both anecdotes involve large groups simultaneously support the model of correlation and clustering presumably from single extremely infectious sources?
Combined with observations of significantly decreased contagiousness from vaccinated people I would expect such events to become much rarer when completely naive people are rare. Consider the dynamics here, ~6 apparently infected in one event and then only two of those continuing to pass it on at all, a sub-replacement chain in that different context.
and then only two of those continuing to pass it on at all
I’m not sure this is the case. I think there was significant stagger between when the girls started showing symptoms, and I don’t know how many have gotten sick since then or who will get sick soon. My wife just started showing symptoms today, for example (though that’s not evidence of vaccinated->vaccinated transfer because kid).
If I had to bet, I’d guess that it was sub-replacement among vaccinated, I just don’t have all the data in front of me yet
My wife and I went to a wedding last week, and 6 of the 14 girls who went to the bachelorette party (all vaccinated) have since tested positive for covid. I and another one of the guys (also vaccinated) got it a few days later, most likely from one of those girls (and not our partners, who both tested negative).
It’s just a few cases, but nonetheless seems hard to square with the lower bound of vaccines still working super well to prevent symptomatic infection.
What kinds of vaccines did you guys have? Also how long ago? I hypothesize a lot of the difference in efficacy reported by the UK (88%) and Israel (64%, kind of close to the efficacy in your situation if we make the generous assumption that all 14 would have been infected without the vaccine) has to do with the fact that Israel started vaccinating earlier.
Also remember most people in the UK had the second dose at 8-12 weeks after the first.
I got my first shot of Pfizer in September and the second in February. I don’t know the exact answer for everyone else, but at least one J&J and I think mostly mRNA, probably at about the time it became available to 30 year olds in the states.
Any given observation can of course but squared with any given level of effectiveness, because randomness, and also because superspreaders are a thing—so the outcomes can be highly correlated.
Hope no one got seriously ill. From the lack of mention of any adverse effects, I am guessing everyone involved is fine?
Yeah, depends on what you mean by “hard” exactly, and what your hypotheses are. If the idea is that the vaccine makes 93% of people completely immune and leaves 7% effectively unvaccinated, then getting at least 6 of 14 should be pretty rare—especially if you expect those 7% to be disproportionately old and unhealthy people and the 14 are all fairly young and healthy. Not impossible, but I’m squinting my eyes and double checking the methodology on anything that implies it was “just a fluke”.
Explanations that assume some correlation are easier to buy, but I’m not sure what it could be correlated with that wouldn’t have also shown up enough pre-delta that we’d have heard of some superspreader event where vaccinated people were passing covid to other vaccinated people.
Too early to tell, but I think everyone will be fine. So far no one high risk has gotten sick.
EDIT: I have some more anecdotal evidence. My cousin just told me that his friend has nearly the exact same story with his wife’s bachelorette party. 6⁄15 so far with symptoms and positive tests, all vaccinated. There’s some selection bias there since I likely wouldn’t have heard about it if it were only 1⁄15, but not enough to make it expected under a “just a fluke” model.
Could the fact that both anecdotes involve large groups simultaneously support the model of correlation and clustering presumably from single extremely infectious sources?
Combined with observations of significantly decreased contagiousness from vaccinated people I would expect such events to become much rarer when completely naive people are rare. Consider the dynamics here, ~6 apparently infected in one event and then only two of those continuing to pass it on at all, a sub-replacement chain in that different context.
I’m not sure this is the case. I think there was significant stagger between when the girls started showing symptoms, and I don’t know how many have gotten sick since then or who will get sick soon. My wife just started showing symptoms today, for example (though that’s not evidence of vaccinated->vaccinated transfer because kid).
If I had to bet, I’d guess that it was sub-replacement among vaccinated, I just don’t have all the data in front of me yet
I think the point Zvi is trying to make is that overdispersion is still a thing, even with people being vaccinated.