It’s been a week since the Centers for Disease Control and Prevention issued new masking guidance based on evidence that vaccinated people can become infected and transmit the more contagious delta variant to others. Many people who thought the vaccines allowed them to return to pre-pandemic normal are now asking whether they need to change how they go about their daily lives.

While delta does change the risk calculus, it doesn’t mean that we have go to back to hunkering down at home. When deciding which activities to engage in, vaccinated people should consider two factors: the medical risk of your household and the value of the activities to you.

A new iteration of the delta coronavirus variant is popping up around the globe, bringing questions and concerns. Here's what we know so far. (John Farrell/The Washington Post)

Someone who is vaccinated, generally healthy, and either living alone or sharing a household with others who are also vaccinated and healthy might decide that they are protected enough that they won’t change anything. According to CDC data, the vaccinated are approximately eight times less likely to become infected than the unvaccinated. Even if they contract covid-19, chances are excellent that a vaccinated person will experience symptoms akin to the common cold; after all, the vaccines reduce the chance of severe illness by a whopping 25-fold.

But isn’t that the cautionary tale from Provincetown, Mass. — didn’t revelers letting their guard down lead to around 965 people becoming infected, including many who were vaccinated? The CDC directly cited this outbreak in urging the vaccinated to resume masking.

That’s one interpretation of the data — it’s true that vaccines are not bulletproof armor and breakthrough infections can happen. Consider, though, that an estimated 60,000 people gathered in Provincetown over the Fourth of July holiday. Restaurants, bars and house parties were packed to the brim. Some of the infected reported prolonged close contact with others. Another conclusion is that this was the ultimate stress test of the vaccines and they passed with flying colors: Only about 1.6 percent were infected, just seven were hospitalized, and no one died.

If the attendees were told of these odds in advance, it’s likely that many who have underlying medical problems or are more risk-averse would have taken additional precautions. Some might not have gone. But there will be those who would still say that the value of the get-together was so high that they would have taken the risk and not changed anything.

What about people who might not worry for themselves, but who live with unvaccinated or immunocompromised family members? That’s the situation I’m in, with two young kids, and my husband and I are careful because of them. My advice for those in our situation is to continue the activities you care about while reducing risk. Eat at a restaurant but dine outdoors. Keep your flight plans but wear a high-quality mask the whole time. Go to the gym but during off-hours when you have more space to yourself.

There may be high-risk events that are worth the possible exposure because of their value to you. If you can’t take precautions during the event, quarantine for at least three days afterward and then get tested. Maybe you normally avoid indoor gatherings with unmasked and unvaccinated people but you make an exception for your sister’s wedding. Maybe you reduce business travel when you can but still attend an important in-person conference. Maybe you’re a grandparent who took a long-awaited vacation that involved lots of dining out. Consider taking additional precautions before you spend time indoors with vulnerable family members.

Remember that vaccinated people are safest around others who are fully vaccinated, too. The CDC has not said this, but I believe a workplace that enforces a vaccine requirement can make masks optional if it’s located in a jurisdiction where that is permitted. If others around me have an eight-fold lower chance of getting infected, and I have an eight-fold lower chance of contracting covid-19 from them, that’s low enough risk for me. This applies in social settings, too; I’d attend an indoor dinner party with all vaccinated people, even if someone there might be engaged in high-risk behavior. But I wouldn’t have this person around my children unless they first quarantine and test. The only adults in close contact with our kids are those who also have a low-risk lifestyle — who spend time with only vaccinated people and mask in indoor public places.

Note that my recommendations leave the decisions to the individual. The vaccinated constitute a small minority — some estimate it to be less than 6 percent — of total coronavirus cases. Israel, which does much better contact tracing than the United States, reported that 80 percent of those vaccinated did not infect anyone in public spaces. Even if we asked the vaccinated to significantly restrict their activities, it would hardly make a dent in total infections, and it could be a major disincentive to vaccination. We should help guide the vaccinated to make the best decisions for themselves and limit any restrictions to those truly endangering the public’s health — the people still choosing to remain unvaccinated.