“A vaccinated friend attended an indoor gathering of 35 people, half of which were unvaccinated. Nobody wore masks or socially distanced. I am vaccinated, but should I avoid contact with this person for some period of time? I am concerned that my friend may have inadvertently been exposed to variants, although no problems as of three days post-event.”

The scenario you describe is likely to be low risk to you and your friend because you’re both vaccinated. It’s not ideal — mostly from the perspective of the people at the meet-up who weren’t vaccinated yet. When non-immunized and immunized people gather in a space, precautions should account for those who haven’t had their shots yet, the Centers for Disease Control and Prevention advises. Those precautions include everyone wearing masks inside in public or indoors if there’s a multi-household mix of people who aren’t vaccinated.

Mingling indoors without masks or distancing is “likely low risk for the vaccinated people,” the CDC writes (the emphasis is the agency’s). That’s because the vaccines are so protective. 

Real-world results continue to support clinical trial conclusions that coronavirus vaccines are highly effective at preventing symptomatic covid-19. In a CDC study of almost 2,500 fully vaccinated health-care workers, only three had confirmed infections. “Front-line workers were 90 percent less likely to be infected with the virus that causes covid-19,” an epidemiologist and author of that study told The Post last month.

Emerging reports also suggest vaccines hinder asymptomatic infection. Two doses of an mRNA vaccine reduced that by 92 percent in Israel, according to a study published this week in The Lancet. And there’s encouraging news that vaccines protect against variants of concern. As we mentioned above, and reported Wednesday, research in the New England Journal of Medicine showed the Pfizer-BioNTech vaccine was “90 percent effective at blocking infections caused by the B.1.1.7 variant,” which is the more transmissible variant first detected in the U.K. The vaccine was slightly less effective, at 75 percent, against the B.1.351 variant identified in South Africa.

It’s good to hear that there haven’t been any problems in the days after this gathering. From what you’ve described, it doesn’t sound as though your friend needs to take any actions like quarantining. In fact, the CDC advises quarantine is generally unnecessary for fully vaccinated people, even after known exposure, unless an immunized person begins to show symptoms.

That said, you’ve asked journalists, not doctors — here’s our usual disclaimer to consult your primary-care physician if you have specific concerns about your susceptibility to the virus. If you’re wary about jumping back into social life, that’s okay, too, and not unusual after living through an ongoing pandemic. Some psychologists suggest easing into social situations post-vaccination, borrowing from principles of exposure therapy; for instance, if you’re anxious and would like to take extra precautions for your next visit with your friend, you might suggest meeting up while outside or you can wear a mask.