Over 15,000 fully vaccinated Massachusetts residents have now tested positive for COVID-19 and more than 130 of them have died, according to state data on breakthrough cases published Tuesday.
The breakthrough cases remain a tiny percentage -- about 0.35% -- of the more than 4,449,267 people who have been vaccinated and the deaths an even smaller percentage -- just 0.0003%
In the last week alone, 3,098 breakthrough cases -- infections in people who have been vaccinated -- have been reported. Health officials said 571 of the new breakthrough cases resulted in hospitalization, or about 0.01% of all fully vaccinated individuals.
Get Boston local news, weather forecasts, lifestyle and entertainment stories to your inbox. Sign up for NBC Boston’s newsletters.
Dr. Philip Landrigan, director of the Global Public Health Program at Boston College, told The Boston Globe last week that the rise in breakthrough cases “reflects the fact that the delta variant is loose in the population, and it reflects the fact that there’s a lot of virus circulating around.”
Experts also told the Globe the increase in breakthrough cases is attributable to diminishing immunity from the COVID-19 vaccines, emphasizing the need for booster shots in the coming months.
Tuesday's report pushed the state's cumulative confirmed COVID-19 caseload to 699,177 since the start of the pandemic and its death toll to 17,825.
Overall case numbers have been on the rise in Massachusetts and nationwide for weeks as the highly infectious delta variant spreads, including among those who are fully vaccinated, but health experts have repeatedly stressed that vaccinations reduce the risk of serious injury or death in the rare breakthrough cases.
If you still need to be vaccinated, here's a tool to find the closest vaccination provider to your home.
Tufts Medical Center Epidemiologist Dr. Shira Doron put the rare deaths among fully vaccinated people into context in a recent conversation with NBC10 Boston.
"We do need to put some of these numbers in a more realistic context just so people, you know, so people don't panic, so people make the right decisions based on the actual risk," Doron said.
She noted that some of the vaccinated patients reported as COVID hospitalizations and COVID deaths are actually due to other underlying issues, where COVID is identified on routine admission screening.
"In those cases, the positive test might be old, a false positive, an asymptomatic positive, a mild infection or an infection that is contributing to the illness or death of someone sick with another primary illness but not the sole cause of it," Doron said.
She said that while breakthrough cases are concerning, they're not as concerning as the need for vaccinations worldwide.
"Most data, with some notable exceptions, suggest that effectiveness against the delta variant is maintained, with only negligible decrement compared to alpha," Doron said of the vaccines.