The CDC said the number of COVID vaccine breakthrough infections reported to the agency are an undercount of all SARS-CoV-2 infections among fully vaccinated persons, especially of asymptomatic or mild infections.
In addition, national surveillance relies on passive and voluntary reporting, and data are not complete or representative, according to the CDC.
Massachusetts health officials on Tuesday reported nearly 4,000 new breakthrough cases over the past week, and 46 more deaths, according to NBC Boston.
In the last week, 3,741 new breakthrough cases were reported, with 125 more vaccinated people hospitalized.
This brings the total number of breakthrough cases in Massachusetts to 40,464 — out of 4.63 million vaccinated people — and the death toll among people with breakthrough infections to 300.
According to the Vermont Daily Chronicle, which cited statistics from Vermont’s Department of Health, 76% of the state’s COVID fatalities in September were breakthrough cases, with just eight of the 33 Vermonters who died being unvaccinated.
As of Tuesday, 88% of all eligible Vermonters age 12 and over had been vaccinated with at least one shot.
Health Department spokesperson Ben Truman said most of the vaccine “breakthrough” fatalities were elderly. Because they were among the first vaccinated, Vermont’s elderly “have had more time to potentially become a vaccine breakthrough case,” he said.
According to The Washington Post, Dr. Peter Marks, director of the U.S. Food and Drug Administration’s (FDA) Center for Biologics Evaluation and Research, said Tuesday updated data might make a strong case in support of everyone 18 and older being eligible for COVID vaccine boosters, but the agency will have to see whether its outside advisers agree.