https://www.scientificamerican.com/article/what-the-cdc-guidelines-for-vaccinated-people-mean/

On Monday, the U.S. Centers for Disease Control and Prevention issued new guidelines on how fully vaccinated people can gather with others. The recommendations state that those who have completed a vaccine series or have gotten a single-shot vaccine more than two weeks prior can visit with one another indoors without masks or six-foot social distancing. And the CDC says that such individuals can similarly visit unvaccinated people from a single household if everyone in that household is at low risk of developing a severe case of COVID-19. Fully vaccinated people are no longer required to quarantine or get tested if they are exposed to someone with COVID but do not develop symptoms (at least for the first three months post–full vaccination). But fully vaccinated people who live in non-health-care settings such as prisons or group homes should still quarantine after exposure, according to the CDC’s recommendations.

Scientific American discussed the new guidelines with Nahid Bhadelia, an infectious disease physician and medical director of Boston Medical Center’s special pathogens unit.