BOSTON — A majority of the recent COVID-19 clusters in Massachusetts are tied to infections passed among family members and roommates, according to state data, which has health experts worried about the holidays.
Of 13,178 new infections stemming from COVID-19 clusters between Oct. 11 and Nov. 7, the state found 11,268 cases tied to households, according to the state Department of Public Health’s latest weekly report.
Nursing homes and long-term care facilities reported the second-highest number of new cases tied to clusters during that timeframe, or 518, according to the report. Prisons, child care centers, colleges and restaurants were also listed as sources of new infections tied to clusters.
Overall, the state reported more than 4,800 COVID-19 clusters during the four-week period. Most of those, or 92%, involved infections spread within a household.
Health officials generally define a COVID-19 cluster as a situation where two people living at the same address or with a “common exposure” test positive for the virus. The state closes cases on clusters after 28 days, or two incubation periods, from the last confirmed positive test in the group.
Gov. Charlie Baker has warned people ahead of the holidays to rethink plans to travel or gather with relatives.
“If we treat this year just like we treat every other Thanksgiving, it’s quite likely that it will trigger a significant spread,” Baker said during a briefing Wednesday. “And we know that that leads to serious illness for many and in rare cases death, especially among our senior citizens.”
On Wednesday, the state reported 2,744 new COVID-19 cases from 97,636 people tested, with a seven-day average positivity rate of 3.31%, according to the health department. Overall, it has reported more than 190,000 cases and more than 10,000 deaths.
As of Sept. 12, 30 communities — including Lawrence, Methuen and Lynn — were deemed “high risk” for the transmission of COVID-19.
Other states are taking drastic steps to prevent “living room spread” of the virus as cases surge amid a second wave of the outbreak.
Vermont Gov. Phil Scott has banned “multihousehold gatherings” ahead of the holidays. He said those get-togethers have led to more COVID-19 infections than restaurants.
“I know this is difficult and frustrating, especially with the holidays right around the corner,” Scott posted on social media. “But it’s necessary.”
Massachusetts has a stay-at-home advisory in effect, a statewide mask requirement and a limit on indoor gatherings to 10 people. The state has also set restrictions on travelers from all but a handful of neighboring states, requiring visitors to present a negative COVID-19 test or self-quarantine for 14 days.
Health experts say the holidays will be a crucial test of the public’s ability to wear masks, practice social distancing and follow other precautions.
“It’s a time for increased transmission,” said Dr. Howard Koh, a professor at Harvard University’s T.H. Chan School for Public Health. “We’re concerned that with all the travel and households mingling that we’ll see a steep rise in infections.”
Koh, a former assistant secretary at the U.S. Department of Health and Human Services, said the risk of getting together could be deadly for some families.
“If they haven’t already, every family should be having an explicit public health discussion about the risks and benefits of getting together,” he said.
Christian M. Wade covers the Massachusetts Statehouse for North of Boston Media Group’s newspapers and websites.