What research says about whether vitamin D can prevent Covid-19, the Covid-19 symptoms likeliest to linger for at least six months, and more.

How much is asymptomatic spread driving Covid-19? Here's what the evidence says. (Monday, January 11)

A new CDC model sheds light on how many coronavirus cases are driven by people who exhibit no symptoms of Covid-19—and experts say the model's findings are even more concerning in light of the emergence of a new, more contagious variant of the virus.

These Covid-19 symptoms are likeliest to linger for 6 months—or more (Tuesday, January 12)

A significant majority of patients who've been hospitalized for Covid-19 still had at least one symptom of the disease six months after they'd recovered from their initial coronavirus infection, according to a first-of-its-kind study—and some long-term symptoms were more common than others.

How Marc D. Miller and his father built UHS—and where Marc's taking the $11.4B system next (Wednesday, January 13)

In this edition of "Lessons from the C-suite," Marc D. Miller, CEO and president of Universal Health Services, talks with Advisory Board President Eric Larsen and OptumInsight CEO Robert Musslewhite about succeeding his father at the helm of the $11.4 billion health care organization, delivering industry-leading health care outcomes while staying under the radar, providing "whole person" care before it was a buzzword, and more.

Can vitamin D really prevent Covid-19? Here's what the evidence says. (Thursday, January 14)

Vitamin D supplement sales have soared amid the pandemic based on early suggestions that it might help prevent Covid-19—but how strong is the evidence of the vitamin's benefits? Here's what we know so far.

Are two face masks better than one? Here's what researchers say. (Friday, January 15)

Many prominent people, from football coaches to senators, are "double-masking" in public in an effort to reduce their risk of coronavirus infection. But is this actually an effective tactic—and if so, what's the best way to do it? Here's what leading researchers told Katherine Wu of the New York Times.