Seventy-year-old Richard Rossner was fully vaccinated when he went to a Los Angeles club to hear his son’s band play. He was careful to social distance and didn’t think he was vulnerable. That was Tuesday night; by Saturday morning, he couldn’t get out of bed. It was Covid. Then his wife, who was also vaccinated, got it. Now that they no longer test positive, they are grateful, but the after-effects leave Richard tired and cautious.