Herd immunity went from a phrase most of us had never heard of to the thing we're all waiting for in just about a year's time. "It's kind of shorthand for back to normal," said Dr. Bob Wachter, chair ...

Herd immunity is the name for a point in time when it's hard for a disease to spread through a group of people. The idea of herd immunity works for some diseases, such as measles. But it's a harder ...

Drivers line up at the entrance of Montgomery County's first mass coronavirus test center in Upper Dublin Township on March 20, 2020. (U.S. Air National Guard photo by Senior Airman Wil Acosta) “Herd ...

You might have heard of herd or community immunity, when a vaccinated portion of a population (aka "the herd") provides unvaccinated people with some protection from a contagious disease. Thanks to ...

To stop the spread of an infectious disease like measles, you don’t have to vaccinate everyone. But you do have to vaccinate many. Just how many? To let you discover for yourself, we simulated an ...