Nearly 4,000 fully vaccinated people in Massachusetts have tested positive for COVID-19, according to recent data from the state Department of Public Health.
The number of breakthrough cases in the state has been infrequent so far — accounting for approximately one in 1,000 vaccinated people.
As of June 12, there were 3,791 coronavirus cases among the more than 3.7 million fully vaccinated individuals in Massachusetts, reports said.
“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, according to the Boston Herald. “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,” he continued. “In some cases, they’ll be shedding such low levels of the virus and won’t be transmitting to others.”
According to the Centers for Disease Control and Prevention, large-scale clinical studies have found that COVID-19 vaccination prevented most people from getting the virus. Still, no vaccine is 100% effective at preventing the disease and there will be “a small percentage of fully vaccinated people who still get sick, are hospitalized, or die from COVID-19,” the agency said.
A recent study from the CDC showed that Pfizer and Moderna are about 90% effective against infection two weeks after the last dose has passed. The one-dose Johnson & Johnson vaccine is about 72% effective against moderate to severe disease, according to U.S. trials.
“Testing to identify current infection remains critical to control of COVID-19,” a DPH spokeswoman told the paper. “People with current infection can spread the virus to others and isolation of cases and identification of close contacts (individuals who may have been exposed) is a foundation of public health response.”
Health officials also warned about the contagious Delta variant, seen in areas in the U.S.
Todd Ellerin, director of infectious diseases at South Shore Health, expressed the need to get as many people vaccinated due to the highly contagious variants.
He made the plea as new virus cases were at record lows in the state last week amid the vaccine rollout.
As of Monday, more than 150 million people in the U.S. have been fully vaccinated, according to the CDC.