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Mass.  reports 4,378 new breakthrough cases for the past week


There were 37 other deaths among those vaccinated.

Dominique Donna (cq), CEO of Boston Caribbean Network Televison (cq), had gritted teeth when he saw his 17-year-old son get his second shot. Now his turn for his first blow, he narrowed his eyes in anticipation of the pain. (Photo by Pat Greenhouse / Globe staff)

The number of breakthrough new cases of COVID-19 in people vaccinated this week was slightly lower than last week, but thousands across Massachusetts are still reporting breakthrough infections.

The state released updated data on Tuesday on the number of COVID-19 cases, hospitalizations and deaths among those vaccinated in Massachusetts. There were a total of 36,723 breakthrough cases of COVID-19 as of September 25, an increase of 4,378 from September 18. Between September 11 and September 18, 4,568 breakthrough cases were reported, so 190 fewer breakthrough cases were reported this week.

There were 4,610,534 people vaccinated as of September 15, which means 0.80% reported a breakthrough case of COVID-19. The rate has continued to rise – it was 0.23% on August 7.

However, another way to understand the prevalence of breakthrough cases is to compare how many of the total number of newly reported COVID-19 cases are breakthrough infections.

Between September 19 and 25, 10,446 people tested positive for COVID-19 and 4,378 breakthrough cases were reported. Thus, 41.9% of COVID-19 cases during this period were breakthrough cases. The previous week, 39.4% of COVID-19 cases were breakthrough infections.

Time and time again, health officials like Dr Ashish Jha and Dr Anthony Fauci have said breakthrough infections do not mean a vaccine fails. A blog post published in August by MIT Medical warned people to expect that “in places with high vaccination rates, those vaccinated will constitute a high percentage of new cases.”

“Among those unvaccinated, about 1 in 20 infections results in hospitalization and 1 in 200 results in death,” Jha wrote on Twitter on September 14. “Vaccines reduce everyone’s risk by 90%.

Hospitalizations and deaths are also increasing, but at a much slower rate. Data for Tuesday showed a total of 1,155 hospitalizations and 254 deaths, an increase of 154 and 37 respectively since September 18. Thus, of those vaccinated, 0.03% were hospitalized and 0.006% died. According to the data, 3.14% of rupture cases resulted in hospitalization and 0.69% resulted in death.