The state on Wednesday reported the highest one-day total of COVID-19 cases during the pandemic, a new, grim number that some medical experts saw as a potential sign of a feared post-Thanksgiving surge.
The number of confirmed cases rose by 4,613, bringing the state’s total to 225,787, state public health officials said. The death toll from confirmed cases increased by 46 to 10,588, the Department of Public Health reported.
Dr. Abraar Karan, an internal medicine physician at Brigham and Women’s Hospital and Harvard Medical School, said it is too soon for Thanksgiving-related infections to show in hospitalizations and death rates, but Wednesday’s record case count could be a reflection of people exposed to the virus during holiday activities last week.
“If people had transmission happen over Thanksgiving week, median incubation period is about five days, so presumably if people came in and got tested … we would start to see a rise in the cases around now,” Karan said.
He cautioned that anyone who was infected at a holiday gathering may have gone on to infect others after returning home, so the rates could continue to rise.
“This is what we feared would happen after Thanksgiving,” Dr. Cassandra M. Pierre, an assistant professor of medicine at Boston University School of Medicine and a physician at Boston Medical Center, said of Wednesday’s dramatic uptick.
“It might still be too soon to tell if this is all Thanksgiving,” she added, “but it certainly does fit in with the accumulated number of indoor gatherings that we know are happening.”
After a summer in which it seemed to have controlled the virus, Massachusetts has been experiencing a second surge. The state has reported case counts in the thousands every day since Nov. 3. Governor Charlie Baker has repeatedly urged people to keep taking precautions such as wearing face masks and social distancing as the holidays approach.
At Nantucket Cottage Hospital, 46 new cases of COVID-19 were reported Monday and Tuesday, prompting schools on the island to shift to remote learning for the rest of the week, officials said.
The hospital confirmed the cases in a statement posted to its website, calling the 46 infections the highest two-day tally “by far” since mid-March. A total of 81 new cases have been identified in the past week, with a seven-day positivity rate of 7.6 percent, according to the statement.
The spike prompted island officials on Wednesday to temporarily switch to remote learning for schoolchildren and to cancel all sports events and school-related activities for the rest of the week, according to a separate statement from Nantucket Public Schools Superintendent Elizabeth Hallett.
Nationally, there were more than 200,000 new cases of the coronavirus reported Wednesday, as the head of the Centers for Disease Control and Prevention said the upcoming months could be “the most difficult in the public health history of this nation” because of the stress on the country’s health care system from the virus.
“The reality is, December and January and February are going to be tough times,” Dr. Robert Redfield said at an event with the US Chamber of Commerce. “I actually believe they’re going to be the most difficult time in the public health history of this nation.”
Redfield warned that total deaths in the US could near 450,000 by February if people don’t follow public health recommendations to mitigate the virus’s spread.
Pierre said such advice is critical, but it has become “background noise” that many people are ignoring, in part because they are tired after more than eight months of following restrictions.
She said many people underestimate their risk of becoming infected because they trust those close to them, though they may not know who they have been in contact with.
“I think people are prone to downgrading the risk that they anticipate from friends and family members,” she said. “I unfortunately continue to see people commuting to work with cousins, with friends, with colleagues, without a mask on.”
“People really need to understand that if someone is not in your household, then they have a different risk profile than you do,” she said. “They potentially pose a risk to you; you potentially pose a risk to them.”
Karan said people need to remain vigilant for a relatively short time before vaccines will become available.
“We are so close to the first vaccines being rolled out,” he said, adding later, “We are getting close to another phase in the pandemic, and I think that alone may be a motivating factor — that you don’t need to do this forever. This is not something that we’re asking you to do for years on end. This is one more major holiday.”
The Department of Public Health also said Wednesday that 45,390 people were estimated to have active cases of the potentially deadly virus, and 1,259 confirmed coronavirus patients were in the hospital.
The public health department also reported that 105,845 more tests had been conducted for coronavirus. The total number of tests administered climbed to more than 8.56 million. New antigen tests had been completed for 4,292 people, bringing that total to 270,281.
The seven-day average rate of positive tests, which is calculated from the total number of tests administered, was at 4.9 percent. The lowest observed figure for that metric — a number watched closely by state officials — is 0.8 percent.
Travis Andersen of the Globe staff contributed to this report. Wire services were also used.