As the first COVID-19 vaccines arrive at hospitals, Gov. Charlie Baker is imploring Massachusetts residents to celebrate the holidays more safely than they did for Thanksgiving — when dinners and informal visits lead to thousands of coronavirus infections and the most stress on the hospital system since the height of the initial pandemic in the spring.

Calling Thanksgiving "a consequential event," Baker said the state can't afford another large surge that would result from unsafe gatherings with friends and family.

"This is once. One time, one month, one year where Christmas, Hanukkah, Kwanzaa, New Year's Eve really do and should be different. Next year, we'll probably be able to celebrate those holidays just like we used to, but not this year," Baker said at his regular COVID-19 media briefing on Tuesday.

Baker said local hospitals started to receive their first shipments of Pfizer's COVID-19 vaccine on Monday, with four hospitals receiving about 6,000 first doses of the two-stage drug.

"Today, the commonwealth is expecting the federal government to ship out 53,625 more doses to 17 more hospitals statewide," Baker said. "This is part of the first 300,000 first doses of the vaccine that are expected to arrive before the end of December."

Secretary of Health and Human Services Marylou Sudders suggested that since holiday gatherings should be limited to only immediate households, families seek out alternative ways to celebrate — like preparing foods for delivery to neighbors, viewing decorative lights from cars, online visits with Santa Claus or virtual caroling with links provided to friends and family.

"I really am really asking people to go deep and really think about next year's celebrations with all those people that we love," Sudders said.

Baker also signed off on further reopening rollbacks in collection of Metro Boston cities and towns that have moved to a modified version of the second phase of reopening, which initially lasted statewide from June 22 to July 6 of this year.

"I want to give locals the ability, if they believe they need to be in a different place, to make that decision because not everybody in Massachusetts is in the same place all the time," Baker said.