While scientists are still learning about BA.5, it’s increasingly clear that compared to past variants, it has advantages that help it bypass the immune system’s defenses. Like other Omicron subvariants, BA.5 has developed new mutations—in this case, in the spike protein, the part of the virus that binds to cells—which may help it to evade immunity, explains Bing Chen, an associate professor of medicine at Harvard Medical School and Boston Children’s Hospital who studies molecular medicine. “Our antibodies are a little less effective against BA.5 compared to BA.1 and Delta,” he says.

BA.5’s increased transmission and our diminished immune defenses mean that COVID-19 transmission outdoors has become more likely. But that doesn’t mean that being outdoors isn’t going to provide some protection—especially if you also take other precautions. As always, context matters. Being in the open air and away from other people is safer than being in a crowd with worse air circulation—like in a packed baseball stadium without a breeze, says Milton. “Outdoors remains a much lower-risk setting than indoors,” says Linsey Marr, professor of civil and environmental engineering at Virginia Tech. “Transmission outdoors is most likely to occur in close, face-to-face conversation. There’s also the possibility of transmission if you happen to be close enough and downwind of someone who is infected.”