Breakthrough Events, From the Omicron Wave Forward

Easier to see recent trends here, on this set of charts which begins in December with the Omicron wave and after many Minnesotans had been vaxed and boosted.  And the trends here look as bad for boosters as the longer term picture did.  Again the way to read these is by comparing the dashed and solid lines of the same color.  If a group’s dashed line is above the solid one, that is quite suggestive of zero effectiveness.  All you need to do is look at the trend over time and in recent weeks and then try to understand how DOH can in good conscience say that boosters are beneficial at this point.  The age group charts suggest they may be for the very oldest, but that just means that performance is worse in all the other age groups.  I will once more point out that DOH has data on potential confounders like testing rates and prior infection, but chooses not to include that.  Draw your own conclusions from that failure.

Dave’s notes:

1. This is our second post showing the proportions of the overall population who are unvaccinated, vaccinated but not boosted, and vaccinated and boosted, along with the corresponding proportions of cases, hospital admissions, and deaths for each subgroup during the Omicron wave. This post on 5/25/2022 is here: https://healthy-skeptic.com/2022/05/25/breakthrough-events-shorter-term-chart/
2. Compared to the last version, this set of charts shows the same data, along with the data for the week of 5/08/2022 which was just published by MDH. The only other changes to the charts were to change the color scheme to match the colors used on the MDH Vaccine Breakthrough web page here: https://www.health.state.mn.us/diseases/coronavirus/stats/vbt.html
3. To recap, on Monday, 5/23/2022, the Minnesota Department of Health (MDH) made some fairly significant changes to their vaccine breakthrough reporting. The biggest change was the addition of booster information to the breakthrough data. They now report cases, hospital admissions, and deaths for those vaccinated but not boosted, and for those who have received at least one booster shot. Also new is the data for the 5-11 age group. Finally, the underlying data files were comprehensively changed, for the positive with the addition of the vaccinated populations, and by providing actual breakthrough cases, admissions, and deaths each week in addition to the rates per 100k.
4. Fig. 1: This chart displays the proportion of the 5 and over population of Minnesota who are unvaccinated (solid purple), vaccinated but not boosted (solid blue), vaccinated and boosted (solid gold), and the proportion of cases among these 3 groups each week (dashed lines of same color). The way to interpret this chart is to compare the proportion of breakthroughs to the proportion of vaccinations. When the dashed line for the proportion of vaccinated or vaccinated and boosted events is below the solid line for the corresponding proportion of population, then the vaccine or booster could be considered to have reduced the number of cases, admissions, or deaths. If the dashed purple line for the unvaccinated proportion of events is above the solid purple line for the proportion of the population that is unvaccinated, then the unvaccinated have a disproportionately higher risk of testing positive, being admitted, or dying. For the week of 5/8/2022, for example, 41% of the population was vaccinated and boosted (solid gold line) while this group accounted for 49% of the cases (dashed gold line). We would interpret this to show that being boosted did not reduce an individual’s chance of testing positive for Covid for that week. For another example, for the first week on the left side of the chart, 12/19/21, the dashed gold line for the boosted proportion of cases line is at 11%, while the solid gold line for the boosted proportion of the population is 28%. This means for the week of 12/19/21 that being boosted is associated with a proportion of cases lower than the proportion of population that is boosted. For the week of 12/19/21 we can see that the lower proportion of boosted cases show up primarily in the unvaccinated, where the unvaccinated proportion of the population is 33% (solid purple line), but they accounted for 47% of that week’s cases (dashed purple line).  In general, it appears that the boosted population is over-represented in Covid cases each week since 3/13/22, while the vaccinated and unvaccinated subgroups are under-represented. For this reason we would argue that the booster is underperforming expectations in terms of preventing people from testing positive for Covid.
5. Fig. 2: Similar to the case proportion chart in Fig. 1, this chart shows the proportion of hospital admissions among the unvaccinated (dashed purple line), the vaccinated but not boosted (dashed blue line) and vaccinated and boosted (dashed gold line) compared to the corresponding proportions of the population (solid lines). We can see that since roughly 3/20/2022 being boosted has had little effect on the odds of an individual being hospitalized, since the proportion of admissions (dashed gold line) is roughly similar to the proportion boosted (solid gold line). Being vaccinated but not boosted has been negligibly helpful since roughly 1/23/2022, comparing the dashed to solid blue lines, but this slight benefit has narrowed for the week of 5/8/2022, the most recent week displayed.
6. Fig. 3: Finally this chart displays the proportion of weekly deaths and to the corresponding proportion of the population. As with cases and hospital admissions, whenever the dashed line is higher than the corresponding solid line then that category is over-represented. We can see, for example, that the proportion of deaths among the vaccinated and boosted peaked at 88% on 3/27/2022, while the boosted population was only 40% of the total population. It is likely that data reporting inconsistencies accounts for some of the choppiness of the data, as well as the fact that there are relatively few Covid deaths each week, so a few deaths can swing the proportions to extremes more easily. In the most recent week, 5/8/22 on the far right side of the chart, the boosted had 44% of the weekly deaths (dashed gold line) but comprised only 41% of the total population (solid gold line), and the vaccinated but not boosted had 22% of the weekly deaths (dashed blue line) but made up 30% of the population (solid blue line). Finally, the unvaccinated had 33% of the weekly deaths (dashed purple line) but made up 30% of the total population (solid purple line). Since the proportion of deaths nearly matches the proportion of the population it is not obvious for the week of 5/8/2022 that being vaccinated or boosted made a significant difference when considering the entire population as a whole.
7. MDH defines the fully vaccinated (what we have termed vaccinated but not boosted) as those who have not received a booster after completing their primary vaccination series, and had been vaccinated at least 14 days prior to testing positive.
8. MDH defines the boosted as those who have received any additional vaccination shots after completing their primary vaccination series, and also received the booster at least 14 days prior to testing positive.