Mass. reports 3,919 new breakthrough cases for the last week

There have been another 32 deaths among vaccinated individuals.

A healthcare worker administers a dose of the Pfizer-BioNTech Covid-19 vaccine at Boston Medical Center in Boston, Massachusetts, U.S., on Thursday, June 17, 2021. Photographer: Adam Glanzman/Bloomberg

Though breakthrough cases continue increasing across Massachusetts, the rates remain low and only a fraction of a percentage of those vaccinated.

The state released updated data Tuesday on the number of COVID-19 cases, hospitalizations, and deaths among vaccinated individuals in Massachusetts. There have been a total of 27,777 breakthrough cases of COVID-19 as of Sept. 11, an increase of 3,919 from Sept. 4. There were 4,549,497 people vaccinated as of Sept. 11, meaning 0.61% reported a breakthrough case of COVID-19. The rate has been steadily increasing — it was 0.23% on Aug. 7. 

Health officials are telling vaccinated people not to be too concerned about breakthrough cases. On Tuesday, Dr. Ashish Jha wrote on Twitter that the estimated 36,000 daily breakthrough infections across the United States shouldn’t be too worrying if you’re vaccinated.


“What does 36K infections mean in terms of hospitalizations, deaths?” he wrote. “Among UNvaccinated, about 1 in 20 infections lead to hospitalization and 1 in 200 lead to death. Vaccines cut risk of each by 90%. Which means daily, 180 vaccinated folks getting hospitalized and about 18 dying.”

Hospitalizations and deaths are also increasing but at a much lower rate. Tuesday’s data showed a total of 823 hospitalizations and 194 deaths, an increase of 61 and 32 respectively from Sept. 4. So, out of vaccinated individuals, 0.02% have been hospitalized and 0.004% have died. According to the data, 2.96% of breakthrough cases resulted in hospitalization and 0.7% resulted in death. 

Jha pointed out that there are about 100 deaths a day in a typical flu season, and noted that deaths from breakthrough infections of COVID-19 can be decreased by getting booster shots to vulnerable individuals.

Dr. Anthony Fauci has repeatedly said that breakthrough infections do not mean the vaccine isn’t working. 

“When you hear about a breakthrough infection, that doesn’t necessarily mean the vaccine is failing,” he said in August. “I think people need to appreciate when you talk about breakthrough infections that the original data from the clinical trial — the efficacy data was based on preventing clinically apparent disease, not preventing infection, such as a symptomatic infection.”


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