The Department of Public Health says 0.1 percent of people in Massachusetts who have been vaccinated against the coronavirus have contracted COVID-19, a finding that highlights how important it is for people to get their shots.
As of Saturday, the DPH said, there were 4,450 “breakthrough” cases of COVID among 4,195,844 vaccinated people.
“Breakthrough case numbers are incredibly low and cases in which the person was hospitalized or died are even lower,” the department said in a statement.
The cases included 303 people who were hospitalized and 79 who died, either in or out of the hospital, according to DPH data. That’s 0.0072 and 0.0019 percent, respectively, of the total vaccinated.
“All available data continue to support that all 3 vaccines used in the US are highly protective against severe disease and death from all known variants of COVID-19. The best way to protect yourself and your loved ones is to get vaccinated,” the DPH said.
The statement noted that, given the state’s high vaccination rates, “we expect to have some vaccine breakthrough cases.” The state is a national leader in vaccinations. As of Monday, 4,273,587 people had been fully vaccinated.
“People who are unvaccinated should continue to wear masks, especially indoors. And individuals who are feeling ill should get tested for COVID-19,” the DPH said.
To get a scientific measure of how effective the vaccine is, experts said, the data on how vaccinated people fared would need to be compared with data on how unvaccinated people fared in terms of getting sick and dying.
“That being said, one thing is obvious. The rates of symptomatic disease, hospitalization and death have all plummeted here as the vaccination rate has increased. Anecdotally, we rarely see severely ill patients who have been fully vaccinated. And all that is happening at the same time as we’ve loosened restrictions. It really feels as if the high vaccination rates we have here in Massachusetts have made an enormous difference,” said Dr. Eric Rubin, a microbiologist and infectious disease physician at Brigham and Women’s Hospital and member of the advisory committee to the Food and Drug Administration that cleared the three vaccines for emergency use in the United States.
“Yes, the vaccines aren’t perfect. We expect that some folks will still be infected. But both in the studies and in real-life evidence they are awfully good,” Rubin, who is also editor in chief of the New England Journal of Medicine, said in an e-mail.
Dr. David Hamer, a physician at Boston Medical Center and a Boston University epidemiologist, said in an interview, “These are really pretty fantastic vaccines.”
At the same time, he said, “The vaccine is not foolproof. It greatly reduces the incidence of symptomatic and even asymptomatic infection. It also reduces severe disease and hospitalization. But it’s not 100 percent protective.”
He said it’s important for as many people as possible to get vaccinated.
“If we get enough of a high level of vaccination coverage, we can greatly decrease transmission, which stops spread and, if you have less virus circulating, you’re going to have less opportunity for new variants to develop through mutation processes,” he said.
“These results provide even more evidence that the vaccines are excellent, not just good, in preventing severe illness and death. We need to accelerate vaccination momentum going forward especially in light of rising national threats from the Delta variant,” said Dr. Howard Koh, a former assistant US secretary of health and former Massachusetts health commissioner who is now a professor at the Harvard T.H. Chan School of Public Health.
The state reported a similar percentage of COVID-19 cases among the vaccinated in late April, when about 2.4 million people had been vaccinated. At that time, no deaths were reported, and data were not available on hospitalizations.
The new figures were released as officials on Cape Cod were keeping an eye on an uptick in COVID-19 cases in Provincetown.
State Senator Julian Cyr, a Truro Democrat who has been one of the leaders of the coronavirus response on the Cape, said a “trend of several cases” had been seen since late last week.
Cyr said the last positive case in the town was on June 4. Those who were infected recently were “overwhelmingly” fully vaccinated, he said.
He said officials were monitoring the situation and working to expand access to testing and vaccinations.
“We are averaging a few cases a day,” Provincetown Town Manager Alex Morse said in an e-mail. “All symptoms are mild.”
The town has among the highest vaccination rates in the state, but it swells in size during the summer, Cyr said. “We do expect to see a low level of positive cases through the summer in communities such as Provincetown that have seasonal populations,” he said.
Martin Finucane can be reached at email@example.com.