Breakthrough Events, March 14

Despite what appears to be extremely slow processing by DOH, it is now apparent that in recent weeks breakthrough events were the majority of all events, likely even more so than the data DOH has released would indicate.  The data lags significantly because of the definition of fully vaxed and DOH’s matching process, so we only have date of event data through early February.  By now I expect the vast majority of events are in the fully vaxed.  Dave’s notes:

1. The table and charts are updated for new data released by Minnesota Department of Health (MDH) on 3/14/2022, adding data for the week starting 2/06/2022 and ending 2/12/2022.
2. The data source for the data on Fig. 1 is the cumulative breakthrough cases, hospitalizations, and deaths published on the MDH COVID-19 Vaccine Breakthrough Weekly Update https://www.health.state.mn.us/diseases/coronavirus/stats/vbt.html
3. The data source for Fig. 2 and Fig. 3 is the data file https://www.health.state.mn.us/diseases/coronavirus/stats/vbtcounts.xlsx found on MDH web page https://www.health.state.mn.us/diseases/coronavirus/stats/vbt.html. The data provided in the data file vbtcounts.xlsx is used without modification, other than to sum the weekly events and compute the breakthrough proportion. Vbtcounts.xlsx provides breakthrough and non-breakthrough cases, hospital admissions, and deaths for each week listed.
4. The data source for the breakthrough proportions by age group (Fig. 4 through Fig. 7) is the data file vbtcirates.xlsx, found on the Minnesota Department of Health (MDH) web page: https://www.health.state.mn.us/diseases/coronavirus/stats/vbtcirates.xlsx . This data file gives the rates per 100k of cases, hospitalizations, and deaths in full vaccinated and not fully vaccinated people, broken out by age group. The rates per 100k in vbtcirates.xlsx are converted into cases, hospitalizations, and deaths by multiplying by the appropriate population. The number of vaccinated people by age group can found on the Vaccine Data page, https://mn.gov/covid19/vaccine/data/index.jsp , in the data file People Vaccinated by Age. The unvaccinated population is found by taking the US Census American Community Survey 5-Year Estimate (Data Table S0101, https://data.census.gov/cedsci/table) and subtracting the vaccinated population. The breakthrough proportion is then found by dividing the breakthrough events by the total of the breakthrough and non-breakthrough weekly events.
5. MDH defines a breakthrough event as a Covid case, hospital admission, or death that occurs 14 or more days after completing the vaccination series (not including boosters).
6. Fig 1: This table is the weekly announced cumulative breakthrough cases, hospital admissions, and deaths, as well as the weekly totals, and change in weekly totals. New breakthrough cases announced on 3/14/2022 total just 2,791 cases. When looking at the change week over week in vbtcounts.xlsx there are not an excessive number of older breakthrough cases, hospitalizations, and deaths, despite the fact that until the end of last week MDH was still reporting, on a daily basis, large numbers of new cases from December, 2021 and January 2022. Presumably these recently reported cases have not been checked yet for vaccination status.
7. Fig. 2 and Fig. 3, Overall Breakthrough Proportions: The overall proportion of breakthrough cases of total cases for the week starting 2/06/2022 was 64.8%, just below the record high of 65.3% for the week starting 1/16/2022. The proportion of breakthrough hospitalizations is at 57.7%, the highest proportion seen so far. Breakthrough deaths were 56.9%, equally the highest proportion last reported on 1/16/2022.
8. Fig. 4 through Fig. 7: Breakthrough Proportions by Age Group: The breakthrough proportion of cases are generally little changed in all age groups for the week starting 2/06/2022. For the 18-49 age group, MDH reported a death rate of 0 per 100k for both the vaccinated and not fully vaccinated, causing the proportion of deaths among the vaccinated to be reported as zero. The proportions for the 50-64 and 65+ age groups are generally running in the same range of proportions seen for the last 4 to 5 weeks. Note that the lower breakthrough proportions reported for the 65+ age group December, 2021 are not being raised as new events are reported. There is no obvious explanation for why breakthrough proportions were low in this time period. We suspect that MDH is behind in evaluating breakthrough cases from this time period due to heavy caseload, but as time goes by this explanation begins to be suspect as well.