So you haven't caught COVID yet. Does that mean you're a superdodger?

Back in the early 1990s, Nathaniel Landau was a young virologist just starting his career in HIV research. But he and his colleagues were already on the verge of a landmark breakthrough. Several labs around the world were hot on his team's tail.

"We were sleeping in the lab, just to keep the work going day and night because there were many labs all racing against each other," Landau says. "Of course, we wanted to be the first to do it. We were totally stressed out. "

Other scientists had identified groups of people who appeared to be completely resistant to HIV. "People who knew they had been exposed to HIV multiple times, mainly through unprotected sex, yet they clearly were not infected," Landau explains.

And so the race was on to figure out why: "Are these people just lucky or did they really have a mutation in their genes that was protecting them from infection?'" he says.

Now 25 years later, scientists all over the world are trying to answer the same question but about a different virus: SARS-CoV-2.

By this point in the pandemic, most Americans have had.