The flu virus is changing in ways never seen before, increasing infections and raising concerns about vaccine effectiveness ...

A new study says the flu A viral strain can adapt shape to stay infectious. Infectious disease doctors break down what this ...

There are two broad types of influenza — flu A and flu B — and many strains within those, but the current spike in flu cases ...

Delays in CDC analyses of infectious disease threats and agency silence will harm Americans, doctors and ...

For a second time this season, at least 41 states are reporting high or very high levels of the flu. Here's how to stay safe.

H5N9 is “not commonly seen in poultry in general,” says Eman Anis, assistant professor at the University of Pennsylvania ...

At least 24 million illnesses, 310,000 hospitalizations, and 13,000 influenza-linked deaths—including 57 children—have ...

Liubomyr Vorona/iStock / Getty Images Plus According to the CDC, there are two other types of flu viruses: C and D. Influenza C typically only causes mild illness and is not thought to cause human ...

Wisconsin is among 10 states to report human cases of the H5N1 virus so far, with more than half reported in California.