Today, that same vaccine is gaining renewed attention from researchers — including those brothers, who all grew up to be virologists — as a possible weapon against the new coronavirus, based in part on research done by their mother, Dr. Marina Voroshilova.

Dr. Voroshilova established that the live polio vaccine had an unexpected benefit that, it turns out, could be relevant to the current pandemic: People who got the vaccine did not become sick with other viral illnesses for a month or so afterward. She took to giving the boys polio vaccine each fall, as protection against flu.

Now, some scientists in several countries are taking a keen interest in the idea of repurposing existing vaccines, like the one with live poliovirus and another for tuberculosis, to see if they can provide at least temporary resistance to the coronavirus. Russians are among them, drawing on a long history of vaccine research — and of researchers, unconcerned about being scoffed at as mad scientists, experimenting on themselves.