…I know, I know, I’m never satisfied. But D.C. has done a good job with its new breakthrough infections panel on its vaccination dashboard (click “Breakthrough Infections” on the right, then click “Case Rates” on the left). But given the data D.C. has, there are two questions D.C.’s public health data could help answer.
First, are breakthrough infections more likely in people vaccinated with the Pfizer vaccine versus the Moderna vaccine after several months? A recent study from Minnesota concluded this was the case. The study was detailed in how it characterized the infected and non-infected patients (i.e., they could match people with similar illnesses and so on). But a significant problem is that they didn’t have information on how often people vaccinated with the two vaccines were exposed. In D.C., some wards are heavily vaccinated with low COVID-19 prevalence (e.g., Ward 3), while others are more like… Southwest Missouri. You can’t have a breakthrough infection if you’re not exposed.
In addition, a hunch, based on personal observation (and I could be completely wrong here) is that some wards were far more likely to get vaccinated with the Moderna vaccine and vice versa. In Ward 2, for example, most of the drug stores are offering Moderna, and the closest public D.C. facility (the Convention Center) was offering Moderna (most of the time), while east-of-the-river, there were more opportunities to have Pfizer vaccines administered–though again, I could be way off-base on this. You rub all of this together, and much of the ‘Moderna advantage’ might disappear.
The second question is how does the level of vaccination and prevalence of COVID-19 influence breakthrough infections? Above I mentioned some possible confounding factors, but there are others, such as age. Seventy year-olds probably are being more cautious than twenty year-olds, and that too, influences the likelihood of exposure (and thus a breakthrough infection).
D.C. has the information on prevalence in each ward, as well as the location of breakthrough infections (most of them, anyway), so the data are really granular. This study could–and should–be done.
So, kudos to D.C. Health for a good dashboard, but they have an opportunity to answer two very important questions. They need to seize it.