We know the people most at risk from Covid-19 are older adults and those with underlying health conditions. But scientists are also wondering why some healthy young people have also passed away. (1/10) 
There will always be outliers, sure, but could there be something happening biologically that makes some people more susceptible to the virus? (2/10)
Dr. Anthony Fauci told me "I'm fascinated ... by what I would call the pathogenesis" when I interviewed him for my podcast, "Coronavirus: Fact vs. Fiction." (3/10)
cnn.it/3alAc9R
cnn.it/3alAc9R
"You know, you get so many people who do well and then some people who just, bingo, they're on a respirator, they're on ECMO (a cardio-pulmonary machine) and they're dead," he said. It was hard to hear, but important. (4/10)
A number of scientists are looking for clues — perhaps in our DNA. (5/10)
covid19hg.org
covid19hg.org
One example: Dr. Philip Murphy told Science Magazine that variations in a gene known as ACE2 -- which yields an enzyme that attaches to cells in the lung -- could make it easier or harder for the virus to get into cells. (6/10)
sciencemag.org/news/2020/03/h…
sciencemag.org/news/2020/03/h…
Another key place to look: how our immune systems respond to the virus. Even in young, healthy people, an overreactive immune response -- a "cytokine storm" -- could lead to massive inflammation and multi-organ failure. (7/10)
Some theories also speculate there could be a link between viral load and disease severity, suggesting that more or prolonged exposure to the virus may lead to worse outcomes. (8/10)
But these are just that: theories. There's so much we don't know about how this virus works and impacts our bodies. (9/10)
As Dr. Fauci told me, "There's something there, Sanjay, that we're missing from a pathogenesis standpoint. And I don't think it's only if you're elderly or if you have underlying conditions. There's something else going on there that hopefully we'll ultimately figure out."(10/10)
