Final peer-reviewed study (again) confirms pretty much everything I've said for the past 2+ years.

UPDATE: It turns out that this is not a "new" study; it's the final, peer-reviewed version of the same pre-print study from last fall by the same researchers, which makes a lot more sense.

Yesterday morning a new study was published at the Journal for the American Medical Association (JAMA) Network website:

Excess Death Rates for Republican and Democratic Registered Voters in Florida and Ohio During the COVID-19 Pandemic

Jacob Wallace, PhD; Paul Goldsmith-Pinkham, PhD; Jason L. Schwartz, PhD

If this study title and its authors sound vaguely familiar, it's because the same three researchers (from the Yale School of Public Health/Management) published a similar study last fall...which I wrote about at the time:

Political affiliation has emerged as a potential risk factor for COVID-19, amid evidence that Republican-leaning counties have had higher COVID-19 death rates than Democrat- leaning counties and evidence of a link between political party affiliation and vaccination views. This study constructs an individual-level dataset with political affiliation and excess death rates during the COVID-19 pandemic via a linkage of 2017 voter registration in Ohio and Florida to mortality data from 2018 to 2021.

We estimate substantially higher excess death rates for registered Republicans when compared to registered Democrats, with almost all of the difference concentrated in the period after vaccines were widely available in our study states. Overall, the excess death rate for Republicans was 5.4 percentage points (pp), or 76%, higher than the excess death rate for Democrats. Post- vaccines, the excess death rate gap between Republicans and Democrats widened from 1.6 pp (22% of the Democrat excess death rate) to 10.4 pp (153% of the Democrat excess death rate). The gap in excess death rates between Republicans and Democrats is concentrated in counties with low vaccination rates and only materializes after vaccines became widely available.

There are some methodology tweaks between their earlier analysis (which was published at the National Bureau of Economic Research) and the one published in JAMA yesterday, but the conclusions are largely identical:

Was political party affiliation a risk factor associated with excess mortality during the COVID-19 pandemic in Florida and Ohio?

...In this cohort study evaluating 538 ,159 deaths in individuals aged 25 years and older in Florida and Ohio between March 2020 and December 2021, excess mortality was significantly higher for Republican voters than Democratic voters after COVID-19 vaccines were available to all adults, but not before. These differences were concentrated in counties with lower vaccination rates, and primarily noted in voters residing in Ohio.

...The differences in excess mortality by political party affiliation after COVID-19 vaccines were available to all adults suggest that differences in vaccination attitudes and reported uptake between Republican and Democratic voters may have been a factor in the severity and trajectory of the pandemic in the US.

...There is evidence that Republican-leaning counties have had higher COVID-19 death rates than Democratic-leaning counties and similar evidence of an association between political party affiliation and attitudes regarding COVID-19 vaccination; further data on these rates may be useful.

...Between January 1, 2018, and December 31, 2021, there were 538 159 individuals in Ohio and Florida who died at age 25 years or older in the study sample. The median age at death was 78 years (IQR, 71-89 years). Overall, the excess death rate for Republican voters was 2.8 percentage points, or 15%, higher than the excess death rate for Democratic voters (95% prediction interval [PI], 1.6-3.7 percentage points).

Note: "Overall" means for the entire period studied, which includes pre-COVID (January 2018 - February 2020), pre-vaccine COVID (March 2020 - March 2021) and post-vaccine COVID (April 2021 - December 2021).

After May 1, 2021, when vaccines were available to all adults, the excess death rate gap between Republican and Democratic voters widened from −0.9 percentage point (95% PI, −2.5 to 0.3 percentage points) to 7.7 percentage points (95% PI, 6.0-9.3 percentage points) in the adjusted analysis; the excess death rate among Republican voters was 43% higher than the excess death rate among Democratic voters. The gap in excess death rates between Republican and Democratic voters was larger in counties with lower vaccination rates and was primarily noted in voters residing in Ohio.

...In this cross-sectional study, an association was observed between political party affiliation and excess deaths in Ohio and Florida after COVID-19 vaccines were available to all adults. These findings suggest that differences in vaccination attitudes and reported uptake between Republican and Democratic voters may have been factors in the severity and trajectory of the pandemic in the US.

There's a bunch of graphs and charts attached, but these two are the most telling to me:

If the first graph looks vaguely familiar, this is why:

Of course the JAMA analysis stops at the end of 2021 (right around the point that the third "red spike" was building up in my own graph). It'll be interesting to see if they publish another update later this year which runs through the end of 2022 as well.

I really don't have much to add here; I've already said everything I have to say about it repeatedly over the past 2 years or so.

And yes, ironically I'm posting this which recovering from a (fairly mild) case of COVID myself, because I stupidly forgot to wear a mask while visiting crowded indoor attractions in Washington DC last week.