Almost 4,000 people in Massachusetts who are fully vaccinated have tested positive for coronavirus, according to new data from the state Department of Public Health.
There have been 3,791 COVID cases out of more than 3.7 million fully vaccinated people as of June 12. That breaks down to 0.1% of vaccinated individuals testing positive for coronavirus in Massachusetts.
The state Department of Public Health did not say how many of the breakthrough infections have been severe, but public health experts tell the Herald that many of such cases are either asymptomatic or mild.
“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 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 added. “In some cases, they’ll be shedding such low levels of the virus and won’t be transmitting to others.”
People who are immunocompromised are at a greater risk for breakthrough cases.
Vaccinated people who have had a known exposure to COVID should get tested if they develop even mild symptoms, according to the state Department of Public Health.
“Testing to identify current infection remains critical to control of COVID-19,” DPH said in a statement. “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.
“The number of COVID-19 cases in MA is low right now and it is important to continue to take appropriate public health action to keep that number low,” the agency added. “The public health recommendation encouraging testing remains in place as we continue to move through this pandemic to monitor for changes in COVID-19 activity.”
Virus cases are at record lows in Massachusetts, as the more contagious Delta variant appears to be taking off in different parts of the country.
With these highly contagious variants, it’s key to get as many people vaccinated as quickly as possible, said Todd Ellerin, director of infectious diseases at South Shore Health.
“We know that the higher levels of neutralizing antibodies you have, the more likely you’ll be protected from these variants,” he said.
Even in Massachusetts with strong vaccination levels, Hamer said it’s important to be “aggressive” and continue to push for vaccine-hesitant people to get the shot.
