Mass. reports 4,568 new breakthrough cases for the last week

There have been another 23 deaths among vaccinated individuals.

Samuel Zizi (cq), 30, of Mattapan, gets his first shot. The Massachusetts Department of Public Health and Tufts Health Plan sponsor an after-service vaccination clinic, outside Our Lady of Mount Carmel Parish (cq), in Mattapan. Staff with Cataldo Ambulance Service (cq) administer the Pfizer-BioNTech COVID-19 Vaccine. (Photo by Pat Greenhouse/Globe Staff)

The rate of breakthrough cases has been getting steadily steeper since the state started tracking cases in July — though they affect less than one percent of those vaccinated —  but the comparative rate of deaths and hospitalizations is low. 

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 32,345 breakthrough cases of COVID-19 as of Sept. 18, an increase of 4,568 from Sept. 11. There were 4,579,627 people vaccinated as of Sept. 18, meaning 0.71% 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. Dr. Ashish Jha and Dr. Anthony Fauci have both noted that breakthrough infections do not mean the vaccine is failing, and deaths are associated with every flu season.


“Among UNvaccinated, about 1 in 20 infections lead to hospitalization and 1 in 200 lead to death,” Jha wrote on Twitter last week. “Vaccines cut risk of each by 90%.”

Hospitalizations and deaths are also increasing but at a much lower rate. Tuesday’s data showed a total of 1,001 hospitalizations and 217 deaths, an increase of 178 and 23 respectively from Sept. 4. So, out of vaccinated individuals, 0.02% have been hospitalized and 0.005% have died. According to the data, 3.09% of breakthrough cases resulted in hospitalization and 0.67% resulted in death.

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