Two months ago, the Centers for Disease Control and Prevention had lifted nearly all rules regarding masks. But on Tuesday, it changed course, recommending that they be worn indoors in parts of the country with high transmission rates, even for people who've been vaccinated.
The CDC guidance that people wear masks in indoor public places applies in parts of the country with at least 50 new cases per 100,000 people in the last week. That includes 60% of U.S. counties, officials said.
Though New England has been among the most vaccinated parts of the country for months, several of its counties, including five in Massachusetts, qualify. However, three New England states don't have any counties that reach the threshold.
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As of Tuesday night, none of New England's governors had issued new mask guidance -- for indoor gatherings or for K-12 schools, where the CDC also recommended everyone wear masks this fall, regardless of vaccine status.
Here is where New England's states stand, based on CDC data showing where COVID transmission is substantial (50-99 cases per 100,000 people) or high transmission (100+ cases per 100,000 people) as of Tuesday evening.
The five counties that qualify in Massachusetts are Barnstable, which has high COVID transmission, as well as Suffolk, Bristol, Nantucket and Dukes counties, each in the substantial zone.
A few cities and towns have recently issued mask advisories or mandates in response to rising COVID testing rates, including Provincetown, the tourist destination with a cluster that's tied to more than 750 cases as of Tuesday.
The CDC's new mask guidance is important, even if Massachusetts is in relatively good shape, said Dr. George Abraham, of Saint Vincent Hospital in Worcester.
"People are traveling all over the country, so they're going to bring back virus with them. People from the unvaccinated states will come up here," he said.
More than 200 medical and public health experts wrote to Gov. Charlie Baker and Education Commissioner Jeffrey Riley Tuesday asking for a mask mandate in schools this year.
"This change will be beneficial, helping keep our children in school, without hybrid learning or long quarantines – but only if masks are mandatory," Quincy pediatrician Dr. Natalya Davis said in one letter.
Belknap County, with substantial transmission, is the only New Hampshire county that meets the CDC metric for recommended mask use.
In Maine, York and Piscatiquis counties meet the CDC threshold for mask use indoors.
The state's top public health official, Maine CDC Director Dr. Nirav Shah, reportedly told the Bangor City Council Monday that a return to indoor mask use is likely coming even for fully vaccinated residents.
None of Rhode Island's five counties have enough COVID transmission for mask use to be federally recommended.
None of Vermont's counties have enough COVID transmission for mask use to be federally recommended.
None of Connecticut's counties have enough COVID transmission for mask use to be federally recommended.