As throngs of Thanksgiving travelers are due to return home to Massachusetts Sunday, public health officials will be keeping a close eye on how the holiday affects the state’s battle against the coronavirus.
Health officials warned that Massachusetts, which was already on an upward trajectory on new coronavirus cases, could see additional infections due to holiday travel. They called on people Saturday to limit next month’s holiday festivities amid the pandemic, and reduce the risk of contracting COVID-19.
“We need to be strong, not generate more cases, and to do that, we need to be careful,” said Dr. Alessandro Vespignani, the director of the Network Science Institute at Northeastern University. “We don’t want to go into lockdowns or things like that.”
And even as Thanksgiving travel was down more than 70 percent over the same time last year due to the health crisis, thousands still traveled through New England’s airports this holiday.
Daniel D. Velez, a spokesman for the Transportation Security Administration, said in an e-mail Saturday that agency officers screened 19,811 people Friday at New England’s six major airports, including Boston’s Logan International.
Nationally, people traveling through airports was 820,399 on Friday, he said. Officials expect Sunday’s passenger volume to be close to, or more than, the roughly 1 million passengers who traveled on Wednesday.
State data released Saturday signaled that the danger posed by the coronavirus has only worsened.
The number of confirmed coronavirus cases in Massachusetts rose by 2,914 Saturday, bringing the state’s total to 214,662. The death toll increased by 40 to 10,441, the Department of Public Health reported.
The state reported 42,549 people were estimated to have active cases of COVID-19 as of Saturday, up 697 from 41,852 reported a day earlier.
The seven-day average rate of positive tests — a number watched closely by state officials, and calculated from the total number of tests administered, grew to 3.6 percent as of Friday, the state reported.
That average figure is the highest the state’s positive rate has been since June 15, when it was 3.7 percent.
Nationally, more than 13.2 million coronavirus cases have been reported, along with about 266,000 deaths, according to data from Johns Hopkins University.
Massachusetts has imposed travel restrictions on virtually every state, including Vermont on Saturday. Hawaii remains the only state without such a restriction.
Earlier this month, the state revised how it determined COVID-19 transmission risks in local communities as Governor Charlie Baker urged leaders to bring students back into classrooms.
But the number of communities at high risk for COVID-19 is soaring. By Friday, the state reported 81 communities that are now considered “high risk,” up from 62 communities a week earlier.
Evidence of coronavirus detected in wastewater at the Massachusetts Water Resources Authority’s Deer Island treatment plant demonstrated the virus’s growing presence in the state.
The pilot program, which officials hope can serve as an early warning system, showed that the amount of coronavirus in wastewater last week reached the highest level yet in the fall surge, according state data.
Dr. David Hamer, a physician at Boston Medical Center and a Boston University epidemiologist, said Saturday people need to curtail their social activities this holiday season.
“People should limit their interactions to small groups of people, especially immediate family, or those they know have been recently tested,” Hamer said. They should “use technology to communicate and see family members, instead of traveling to see them.”
Martin Finucane of the Globe staff and Globe correspondent Jeremy C. Fox contributed to this report.
John Hilliard can be reached at email@example.com.