As Covid-19 cases continue to surge in the United States, scientists are learning more about the delta variant, as well as breakthrough infections, every day. But it can be hard to keep up with the latest findings, Apoorva Mandavilli writes for the New York Times. Here's what you need to know now.

Most people have long believed that metabolisms slow down around middle age, making it harder to control weight. But a groundbreaking study published in Science suggests we may have been misunderstanding metabolism all along, Gina Kolata writes for the New York Times.

FDA on Thursday authorized third doses of Pfizer-BioNTech's and Moderna's Covid-19 vaccines for some immunocompromised people, and CDC on Friday recommended the extra doses for those individuals. Some experts worry, however, that the move will open the floodgates for healthy people to get extra shots they don't qualify for.

Apple says it wants to revolutionize health care by letting physicians monitor patients' health data through their phones and watches. But it's still unclear just how many doctors use such tools—and whether these technologies actually benefit patients, Sarah Kwon reports for Kaiser Health News.

Are mRNA vaccines less effective against delta, how dangerous is the delta variant for kids, and more.

San Francisco has become the second major city to require proof of vaccination to enter indoor businesses, including gyms, restaurants, and entertainment venues, in today's bite-sized hospital and health industry news from California and Tennessee.