As Mari Lenharo writes in Elemental, one of the established facts about Covid-19 is that it hits older people hardest. This is why several stories of centenarians beating Covid-19 piqued the curiosity of geneticist Mayana Zatz who has now launched a study to understand why some elderly people are resilient to the virus. Right now she has six people over the age of 95 who got the virus and survived enrolled in her clinical trial. It’s likely there’s something about their genes that’s keeping them protected. Read about the research below.