“I don’t wear a mask hanging out with other vaccinated people,” said Dr. Ashish K. Jha, dean of the Brown University School of Public Health. “I don’t even think about it. I’m going to the office with a bunch of people, and they’re all vaccinated. I’m not worried about it.”
But once you start to venture into enclosed public spaces where the chances of your encountering unvaccinated people are greater, a mask is probably a good idea. Being fully vaccinated remains the strongest protection against Covid-19, but risk is cumulative. The more opportunities you give the virus to challenge the antibodies you’ve built up from your vaccine, the higher your risk of coming into contact with a large enough exposure that the virus will break through the protective barrier generated by your vaccine.
For that reason, the case rate and vaccination rate of your community are among the most important factors influencing the need for masks. In Vermont, Massachusetts, Connecticut and Rhode Island, for instance, more than 70 percent of adults are fully vaccinated. In Alabama, Mississippi and Arkansas, fewer than 45 percent of adults are vaccinated. In some counties, overall vaccination rates are far lower.
“We’re two Covid nations right now,” said Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine and co-director of the Center for Vaccine Development at Texas Children’s Hospital. In Harris County, Texas, where Dr. Hotez lives, case counts are rising, up by 114 percent in the past two weeks, and only 44 percent of the community is fully vaccinated. “I’m wearing a mask indoors most of the time,” said Dr. Hotez.
Finally, masking is more important in poorly ventilated indoor spaces than outdoors, where risk of infection is extremely low. Dr. Jah notes that he recently dashed into a coffee shop, unmasked, because in his area of the country, infection rates are low and vaccination rates are high, and he was only there for a few minutes.