Public health officials have tracked 4,450 "breakthrough" cases of COVID-19 among Massachusetts residents fully vaccinated against the disease, representing about one-tenth of 1% of the roughly 4.2 million people immunized.
About 92% of the infections in vaccinated residents did not require hospitalizations, while 303 people, or 6.8%, were hospitalized, according to Department of Public Health data through July 10.
The Boston Herald first reported the breakthrough data on Tuesday based on a public records request.
Seventy-nine vaccinated residents in Massachusetts died from COVID-19, either without being hospitalized or following a hospital stay, DPH said. That death toll reflects 1.78% of the 4,450 confirmed breakthrough cases and 0.0019% of the 4,195,844 people fully vaccinated as of July 10.
Health experts have said occasional infections after vaccinations are expected but that the immunizations greatly reduce the chances that contracting COVID-19 will lead to serious complications or death.
Since the pandemic began, DPH has confirmed 665,088 COVID-19 infections and 17,647 deaths — the bulk of which occurred before most residents had access to vaccines — for a fatality rate of nearly 2.7%.
The pace of new vaccinations has slowed considerably in recent weeks leading up to and after the June 15 end of the state of emergency. In the seven-day period ending May 30, the state averaged 41,918 vaccine doses administered per day, but that rate dropped to 10,880 for the seven-day period ending July 2.
Gov. Charlie Baker's administration has ramped up its focus on more targeted vaccine initiatives, supporting door-knocking campaigns, local outreach and incentive programs such as a state-run "VaxMillions" lottery open only to those who are fully dosed.