Those infected with the flu are most contagious during the first three days, the CDC said. In some cases, however, people can spread the flu even before experiencing symptoms or up to five to seven ...

The United States and Mexico are at risk of losing their measles-free status; hundreds of people in South Carolina are ...

When the flu strikes, one of the biggest concerns is how long you might be contagious. Knowing this can help protect your family, friends, and coworkers from catching the virus. This guide from ...

We answer questions about measles, like how contagious it is, if you can still catch if you’re vaccinated and at what point is herd immunity achieved.