Cumulative confirmed deaths since the beginning of the pandemic: 20,884
https://www.mass.gov/info-details/covid-19-response-reporting
Breakthrough deaths: 1,224 (5.86% of confirmed deaths to date)
https://www.mass.gov/doc/weekly-report-covid-19-cases-in-vaccinated-individuals-january-18-2022/download
Cumulative confirmed cases since the beginning of the pandemic: 1,418,149
Breakthrough cases: 348,510 (24.57% of confirmed cases to date)
Breakthrough hospitalizations: 5,437 (0.38% of all confirmed cases to date; cumulative hospitalization data is not available from Massachusetts)
Presenting the data this way, however, leads to mixing the breakthrough data with the data from the first year of the pandemic when there were no vaccines through which to break.
We have to subtract the first year data to see what is really going on since vaccinations began and were characteristic of the second year.
A convenient date to choose for the end of the first year is March 7, 2021, when The Covid Tracking Project ceased its pandemic data gathering efforts. That data helpfully included cumulative hospitalization numbers. And fewer than 10% of Massachusetts residents had been fully vaccinated by that date.
In the first year of the pandemic through March 7, 2021, Massachusetts had 16,085 confirmed deaths, 559,083 confirmed cases, and 19,713 ever hospitalized for COVID.
The hospitalization rate in the first year was therefore 3.525% of confirmed cases, slightly higher than the national rate in the first year of the pandemic at 3.06%.
This means in year two to date since March 7, 2021 there have been only 4,799 additional confirmed deaths, but 859,066 additional confirmed cases and approximately 30,282 additional hospitalizations (I used the first year hospitalization rate of 3.525% as a proxy for this, which I grant is only an educated guess).
From those baseline figures from the second year of the pandemic to date, we get the following rates for breakthroughs since March 7, 2021 using the breakthrough data Massachusetts helpfully reports unlike most states:
Breakthrough deaths: 25.50%
Breakthrough cases: 40.56%
Breakthrough hospitalizations: ~17.95%.
In Massachusetts, the proportion of serious outcomes for vaccinated people is much higher than people realize. This is certainly true for deaths.
