What to expect after a Covid-19 vaccine, from how long side effects last to when protection kicks in

Covid-19 shots from Pfizer and Moderna can carry side effects for a few days. They offer...

10 people in the US had bad allergic reactions to Moderna’s vaccine – after 4 million doses

Your odds of having an allergic reaction in the minutes after receiving Moderna's vaccine...

The 11 most mind-blowing, awe-inspiring health discoveries and innovations of 2020

Not everything was awful this year. Here are 2020's most impressive feats of health, from...

One striking chart shows just how well Pfizer's shot works to prevent Covid-19 infections

Two weeks after the first shot, people who received Pfizer's Covid-19 vaccine showed...

Quarantining is based on 700-year-old virus-fighting logic

14-day coronavirus quarantines were too long for many people to handle. Turns out, most...

How to interpret the 'vaccine efficacy' rates of coronavirus vaccines

Vaccine efficacy is a metric that measures how well cases of an infectious disease, like...

Trump campaign rallies 'likely led to more than 700 deaths' from coronavirus, study finds

"The communities in which Trump rallies took place paid a high price in terms of disease...

Fauci: 5 science-backed reasons you should keep your mask on at all times during the pandemic

"Return to normalcy will require the widespread acceptance and adoption of mask wearing,"...