Nearly 4,000 people in Massachusetts who have been fully vaccinated against COVID-19 have tested positive for the disease, adding to the growing number of breakthrough cases nationwide.
According to the Massachusetts Department of Public Health, as of June 12, there were 3,791 infections among the 3.7 million fully vaccinated people in the state, or about one out of every 1,000 individuals.
“We’re learning that many of the breakthrough infections are asymptomatic or they’re very mild and brief in duration,” said Boston University infectious diseases specialist Davidson Hamer, the Boston Herald reported. “The viral load is not very high.”
“Breakthroughs are expected, and we need to better understand who’s at risk and whether people who have a breakthrough can transmit the virus to others,” Hamer said. “In some cases, they’ll be shedding such low levels of the virus and won’t be transmitting to others.”
So-called breakthrough cases refer to cases appearing two or more weeks after a person’s final shot, that is, the second Pfizer or Moderna dose or the single-shot Johnson & Johnson vaccine.
“There is some evidence that vaccination may make illness less severe.”
The CDC said last month that through April 30, 10,262 breakthrough infections were reported in 46 U.S. states and territories.
Approximately 10 percent of the patients required hospital care, and 160, or about 1.5 percent, died.
Data indicate that about three in 10 hospitalized patients were admitted for a reason unrelated to COVID-19 or with no symptoms.
The median age of those who died after getting vaccinated was 82 years. Twenty-eight deaths were pegged to a cause unrelated to COVID-19 or occurred in patients who displayed no symptoms.
Sequencing data were available for 555 of the breakthrough cases. Over 60 percent were identified as stemming from variants, including the B.1.1.7 variant that was first identified in the United Kingdom.