Break on through (to the other side)

Kevin Roche continues to follow the Covid-19 data and research. His Healthy Skeptic site pierces the fog on a daily basis. Most recently, focusing on Minnesota, Kevin has sought to understand the phenomenon of breakthrough infections. At my request, Kevin provides the following background to his post “Breakthrough Infections, September 27,” which should be consulted together with these comments. Kevin writes:

Vaccines against respiratory viruses historically provide good adaptive immunity, but the immunity is not absolute. We all have to breathe and the vaccines cannot stop exposure to an airborne pathogen, so exposure can occur frequently. However, the vaccines can provide a quick response to exposure and attempted infection — a response which can restrict symptoms, the likelihood of serious illness, and infectiousness.

Assessing the real world effectiveness of a respiratory virus vaccine by monitoring the prevalence of infections and serious disease following vaccination is obviously important and can also provide guidance to improve future iterations of the vaccines. Access to data about infections following vaccination is crucial.

In Minnesota, the Department of Health defines a person as fully vaccinated 14 days after his final dose of a vaccine and refers to infections in these people as “breakthrough” cases. A few weeks ago the state began providing data on infections in fully vaccinated people, including hospitalizations and deaths.

The data, however, are incomplete in important respects. The state identifies fully vaccinated persons from a separate database, and has some capability to include Minnesotans who were vaccinated in a few neighboring states, but is unable to identify Minnesotans who may have been vaccinated in Florida or Arizona, for example. There are quite a few people who fall into that category, so the state’s data are understated.

Weekly on Mondays the state merely gives the number of persons who are fully vaccinated along with the cumulative number of breakthrough cases, hospitalizations and deaths. The department does this because it fits their messaging, which has been that breakthroughs are rare and represent a very small per capita rate of all people who are infected.

This is misleading. While per capita rates can be informative, they should be compared with per capita rates among the unvaccinated and, more importantly, the public should be given data on the relative proportion of cases, hospitalizations, and deaths due to breakthrough infections versus those in the unvaccinated. And please note that the unvaccinated actually includes a number of persons who are in the process of becoming fully vaccinated.

While the state — intentionally I believe — fails to attach dates to breakthrough events, it is possible by estimating data lags to come up with the proportions of breakthrough events. The charts in my recent post provide the per capita proportions of cases, hospitalizations, and deaths in the vaccinated and unvaccinated populations in Minnesota, and the proportion of those events in each population, respectively.

The charts help us understand why the department so desperately seeks to divert attention from the data. We do not in fact currently have an epidemic of the unvaccinated. We have an epidemic that is likely right at this moment evenly split between the two groups and heading toward a majority of the events occurring in the vaccinated population.

There is a data lag of several weeks, but in recent weeks the per capita rates in the respective populations have begun to converge. On the relative proportions chart 40 percent of cases, hospitalizations and deaths occurred in the vaccinated group. September of 2021 saw more deaths than did September 2020 and those deaths are in the elderly, most of whom are vaccinated. When we see the data for September in a couple of weeks I am confident that most events will be among the vaccinated.

I don’t find this alarming. In fact it is what you would expect a vaccine against a respiratory virus. And it doesn’t mean the vaccines don’t work — they do, on a relative basis. But the public should have been given the appropriate expectations and should be given fully transparent and accurate information about breakthrough events. Among other things, this information helps create the realistic understanding that it is futile to imagine that we can eliminate the virus. We can’t and we will live with it just fine.