Gov. Charlie Baker is holding fast to the state's policy that school districts should not return to remote learning, even if schools are experiencing staffing shortages because of COVID-19 infections.

Baker said that if districts need to close schools because of staffing problems, they'll need to use designated professional development days or snow days, and that days spent remotely won't count towards the 180 days of in-class learning the state requires.

"They all have days that are available for a variety of non-instruction-related activities that they bank at the beginning of every school year and most of them have the vast majority of those days available to them now," Baker said in a Monday afternoon press conference.

Boston Mayor Michelle Wu has signaled that the city may shift some classes to remote learning if it has staffing problems. Baker said the state will work with BPS to resolve whether remote days will count toward the 180-day requirement but that he wants the state's schoolchildren in the classroom.

"The best place for kids is in school and that is because, in many respects, every respected public health expert in America has said that the safest place — and, by the way, the healthiest place — for kids is in school," Baker said when asked about Boston potentially returning to remote learning.

Baker also expressed support for the adoption of the state's new COVID-19 vaccination verification system, a website-driven QR code that can help businesses and other entities manage the vaccination status of patrons.

"I think it's a far more customer-friendly and effective way to make this tool available to people if they want to use it," Baker said.

Asked whether the state database that powers the verification system will be up to the task of serving results for millions of vaccinated Massachusetts residents, given the state's dodgy track record on IT stability, Baker said the system has been thoroughly tested. He also suggested the system was capable of handling heavy traffic.

"We ran a soft launch on this over the last couple of weeks and had a lot of people who participated," Baker said.

The Massachusetts Immunization Information System database behind the program will share information with Veterans Affairs and several other states, but Baker said that residents who received immunization shots in some states may need to take additional steps to take part in the Massachusetts program.

"If you got your vaccines in Florida or in New Hampshire or Connecticut or Vermont or New York, you would need to get that information from them. But there's a process on the website that will show you the way you can actually make that happen," Baker said.

Baker also told reporters that he's open to using his power to reduce or dismiss prison sentences for the first time as he reviews clemency cases that are in front of him.

"We've had several conversations about the recommendations that currently are before us, and we recognize and understand that there's a deadline coming and we need to make a decision," Baker said.

Baker will have to decide this week on the case of Brockton's Thomas Koonce, who the state Advisory Board of Pardons has recommended be eligible for parole.

Baker said the fact that his administration has updated the rules and guidelines associated with commutations and pardons less than two years ago was an indication that he is open to relieving some individuals serving long sentences and that he wants prisoners to pursue the process.