Okay this thing isn't going away so let's talk about why 1 in 5000 is actually meaningless and, despite vaccines' relatively powerful protection against hospitalization, breakthrough infections aren't "rare" when community spread is high.

Short thread
The figure comes from the NYT newsletter (reported as the individual *daily* risk of infection among the vaccinated). It was cited by Biden in his new covid response plan (somehow reported as a *weekly* infection risk) and has been otherwise making the rounds. Image
Where does the number come from? NYT guy David Leonhart apparently looked at data from a few arbitrary jurisdictions that track breakthrough infections (UT, VA, King County WA) and decided the numbers were trustworthy and could be applied nationally.
He also cites other arbitrary places where reported breakthrough infections were 1 in 10000. He says: “Here’s one way to think about a one-in-10,000 daily chance: It would take more than three months for the combined risk to reach just 1 percent.”
First problem: few infections, breakthrough or otherwise, are ever confirmed through testing. CDC estimates that overall, there are 3.2 undetected infections for every one that ends up in the data. There's reason to believe this reporting problem is bigger for the vaccinated.
Because vaccinated people tend to have less severe symptoms, and people with milder symptoms are less likely to get a PCR test.
Let's redo the '1% in 3 months' calculation, but choose a place with 1 in 5k reported breakthrough infections (instead of 1 in 10k) and assume the 1:4 ratio for detected:undetected cases holds.

That would be 10% of vaccinated people who develop breakthrough infections in 3 mo
But there's more. We should be cautious about vaccination status in state reports. Everyone is assumed to be unvaxxed unless proven otherwise. If you got your vaccine in another state, at a VA facility, your name doesn't match well across systems, you're considered unvaxxed
Different states have different ways of determining vaccination status and likely have different data quality. Again, this is something CDC acknowledges Image
Also, it's good we're talking about absolute risk among the vaccinated here. That requires us to care about the amount of community spread and specify a time period. None of these "1 in 5000" places were in places like FL or LA where spread was very high.
Call me cynical, but I don't think the Biden admin would be pushing booster shots (despite lack of scientific agreement about how necessary they are) for 100s of millions of Americans if risk of breakthrough infections was negligible
Again, vaccines offer people extremely good protection from hospitalization and death. Getting vaccinated is the best thing you can do to lower your risk. But there's a difference between individual risk and population risk.
And we've been seeing about that about 15% of hospitalizations and deaths in the most recent weeks are people classified as vaccinated. That means if we let 100,000 more people die, 15,000 of them will be vaccinated. There are political implications
When you pursue a vaccine-only strategy, and the vaccination is imperfect, a lot of people who followed the government advice are going to die. That creates political need for a more-perfect vaccine.
And in the meantime, we've seen Biden push for more public health measures, even if it's too little and too late.
People like Jha will also try to convince you that breakthrough infections are no big deal, but that ignores things like transmission risk to the unvaccinated (like children who aren't even eligible) or who aren't protected by vaccination (certain immunocompromised conditions)

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More from @jfeldman_epi

24 Aug
Until pretty recently it was hard to find a political message about addressing climate change in the US that went beyond consumer choice (or worse, overpopulation). Now it's much easier to come across messages, even campaigns that call for regulation, planning, policy change...
That shift reflects years of organizing and education. With covid, the pandemic hit much faster than the left's ability to organize around it, and that first step of internal education is still far from complete.
I was naive bc I assumed that commited leftists would look at the pandemic response through lens of class power, structural racism, intertwined fates. But maybe most people need to be specifically organized around each new issue
Read 4 tweets
21 Aug
Is it just me or did CDC go from "breakthrough infections are rare" to "we need boosters to prevent breakthrough infections" in like a week? And I'm not sure if the first talking point was rescinded.
And please take a moment to consider before you get mad at this
"What was previously uncertain is now revealed to be extra risky and we didn't prepare for it" is called not following the precautionary principle and that is a political stance
Read 6 tweets
6 Aug
Black and Indigenous people are being hit hardest by delta, with 2.4 and 1.8x the hospitalization rate of whites in the US, respectively.

These figures actually understate the inequalities because populations of color are younger than the white population.
Screenshot from CDC's COVIDnet gis.cdc.gov/grasp/covidnet…
COVID-net only covers 10 states, and some states that are being hit particularly hard right now like Florida are excluded
Read 5 tweets
22 Jun
1/ I'm gonna use this to lay out a messy, preliminary version of an argument here. The question I'm trying to answer:

Why did US public health experts generally not push for the kinds of broad shutdowns that our counterparts advocated in many other countries?
2/ The answer is manifold, but I want to focus on one particular aspect here.
3/ Shutdowns are big, blunt instruments of the sort US scientists are socialized to eschew in favor of lightweight, targeted, local intervention. We're told to be pragmatic, that only micro-interventions will actually get adopted bc they’re palatable to politicians and the public
Read 21 tweets
5 Apr
The unstated US pandemic strategy:
- Strongly disfavor policies that interfere with business
- Favor individual behavior change
- Tolerate an unlimited number of deaths
- Intervene more strongly to avoid exceeding ICU capacity (sometimes)
- Rely nearly exclusively on vaccination
Most social distancing in the US has been voluntary. In Jan 2021, you could've eaten indoors in 46 states.

Social distancing has been about individuals choosing to avoid risk to themselves and others. This is far less effective than govt policy and not everyone has a choice
Despite the lax government response, we see a weird type of 'inventing a guy to get mad about' response, wherein people (mainly elites) are upset about social distancing and still want to blame government for doing *too much*.
Read 5 tweets
19 Mar
On Jan 21, Biden signed an executive order stating OSHA would issue an emergency covid regulation by March 15 "if such standards are determined to be necessary". Guess that's not happening.
Apparently they've opted instead to focus inspections on the highest-risk covid sites. But that leaves the vast majority of workplaces unprotected. And without a regulation, it's easier to fight citations under the less specific "general duty clause" osha.gov/enforcement/di…
Can a worker who refuses unsafe conditions then collect unemployment? Biden promised this, but details are still unclear (please let me know if you know something I don't) archive.is/M9RUT
Read 9 tweets

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