Could Genetics Be the Key to Never Getting the Coronavirus?

Last Christmas, as the Omicron variant was ricocheting around the United States, Mary Carrington unknowingly found herself at a superspreader event—an indoor party, packed with more than 20 people, at least one of whom ended up transmitting the virus to most of the gathering’s guests.

After two years of avoiding the coronavirus, Carrington felt sure that her time had come: She’d been holding her great-niece, who tested positive soon after, “and she was giving me kisses,” Carrington told me. But she never caught the bug. “And I just thought, Wow, I...