Here’s what to know about the new mask guidance in Mass.

A window in a front hallway in Cambridge is adorned with face masks.John Tlumacki/Globe Staff

Massachusetts on Tuesday loosened its mask guidance for people who are fully vaccinated against COVID-19, now suggesting only certain groups at higher risk for the virus wear masks indoors.

The new mask recommendation marks a change from the state’s previous guidance that was issued as cases — fueled by the Omicron variant — were rising. In December, the Baker administration said all residents were advised to wear masks in indoor public places, but stopped short of a mandate.

Here’s what you need to know about the new mask guidance.

The Department of Public Health said in a statement that it now recommends fully vaccinated people wear a mask indoors if they meet certain criteria.

People should wear masks indoors if they:

• Have a weakened immune system.
• Are at increased risk for severe disease because of age or an underlying medical condition.
• Live with someone who has a weakened immune system and is at increased risk for severe disease or is unvaccinated.

People who are not fully vaccinated should still wear masks indoors.

Everyone in the state, regardless of their vaccination status, will still need to wear masks in certain settings, including on public transportation and in health care facilities, the Baker administration said.

While the new guidance no longer suggests everyone in Massachusetts wear masks indoors, some cities and towns have implemented stricter measures.

Indoor mask mandates are still in place in multiple cities and towns in the state, including Boston. Individual businesses also set their own rules when it comes to masking.

The Department of Public Health said Tuesday it was making the change “recognizing that Massachusetts is a national leader in vaccine acceptance and in light of recent improvements in COVID-19 indicators.”