The Food and Drug Administration has authorized a fourth dose of Covid-19 vaccines — a second booster — for people 50 and older. But is a fourth dose really necessary, or beneficial? This is a question that health officials worldwide are scrambling to answer. European regulators have said there…

The White House’s roadmap for the next phase of the pandemic covers all the usual suspects, including Covid-19 surveillance, testing, vaccination and treatment. But there’s also a happy surprise tucked in there: a series of proposals to help improve indoor air quality. This marks an essential…

A South African biotech company has recreated small quantities of Moderna’s Covid-19 vaccine. Its achievement, done in partnership with the World Health Organization, is part of a broader plan to help low- and middle-income countries become less reliant on US and European drug makers, which have…

In the pandemic’s third year, we are beginning to discern the total picture of Covid-19’s damage. Beneath the coronavirus’s own staggering death toll and the suffering it has inflicted lie many layers of collateral damage. One of the largest of these is Covid’s disruption to cancer prevention and…