Nearly 45,000 Breakthrough COVID Cases Reported in Mass. Since July

The breakthrough cases represent just a small percentage -- about 0.95% -- of the over 4.8 million people who have been vaccinated

NBCUniversal Media, LLC

Nearly 45,000 fully vaccinated Massachusetts residents have now tested positive for COVID-19 and 345 of them have died, according to the latest state data on breakthrough cases published Tuesday.

The Department of Public Health has tracked a cumulative 44,498 confirmed COVID-19 infections among those fully vaccinated in the state to date.



Watch NBC10 Boston news for free, 24/7, wherever you are.


Get Boston local news, weather forecasts, lifestyle and entertainment stories to your inbox. Sign up for NBC Boston’s newsletters.

The breakthrough cases represent just a small percentage -- about 0.95% -- of the over 4.8 million people who have been vaccinated and the deaths an even smaller percentage -- just 0.007%

In the last week, 4,034 new breakthrough cases -- infections in people who have been vaccinated -- have been reported. Health officials said 148 of the new breakthrough cases resulted in hospitalization. Overall, just 0.03% of vaccinated people have now been hospitalized.

Except for two weeks, the number of new breakthrough cases announced each Tuesday had climbed each week since DPH announced the initial batch of 7,737 breakthrough infections on July 31. This week's data showed an increase of about 300 cases over the previous week. Here's a quick look at how many new breakthrough cases have been reported over the past two months:

  • Oct. 12 -- 4,034
  • Oct. 5 -- 3,741
  • Sept. 28 -- 4,378
  • Sept. 21 -- 4,568
  • Sept. 14 -- 3,919
  • Sept. 7 -- 4,415
  • Aug. 31 -- 3,704
  • Aug. 24 -- 3,098
  • Aug. 17 -- 2,672
  • Aug. 10 -- 4,568

Despite the surge of different variants, faith among Boston-based doctors in the efficacy of COVID vaccines hasn't wavered.

"The biggest threat to people who are vaccinated is the continued spread of delta and other variants among the unvaccinated," said Dr. Daniel Kuritzkes, chief of Brigham and Women’s Hospital's infectious diseases division. "That's really where the reservoir of infection exists and that's where the spillover cases come from."

Tuesday's Department of Public Health report pushed the state's cumulative confirmed COVID-19 caseload to 772,932 since the start of the pandemic and its death toll to 18,394.

Overall case numbers have been on the rise in Massachusetts and nationwide for weeks as the highly infectious delta variant spreads, including among those who are fully vaccinated, but health experts have repeatedly stressed that vaccinations reduce the risk of serious injury or death in the rare breakthrough cases.

Michael Genereux, who tested positive for COVID-19 after being fully vaccinated and visiting Provincetown, describes the sickness he has been feeling for the last week.

Kuritzkes said some breakthrough cases were always expected in Massachusetts, but the numbers remain very low.

"It's to be expected that in a state where a majority of people are vaccinated that you will see, when there are cases, that there will be cases in the vaccinated population based over makeup a tiny fraction of the total vaccinated population, because the vast majority of people remain highly protected," he said.

"We really need to focus on dispelling the misinformation," Dr. Shira Doron of Tufts Medical Center said. "We really need to get vaccines into the arms of people in other parts of the world that want to be vaccinated but haven't been able to do so. That's where the next variants will emerge."

If you still need to be vaccinated, here's a tool to find the closest vaccination provider to your home.

Contact Us