All four flu pandemics — in 1918, 1957 and 1968 and the swine flu pandemic of 2009 — were caused by Type A viruses. Influenza B viruses, however, only circulate in humans. They are divided ...

New Type of Antibody Shows Promise Against Multiple Forms of Flu Virus Dec. 21 ... A responsible for the 2009 H1N1 pandemic -- pdm09 -- shows that the virus has passed from humans to swine ...

Flu A and flu B are two different strains of influenza, explains Thomas Russo, M.D., professor and chief of infectious ...

Two types of influenza viruses are responsible for seasonal ... and pigs (such as in the 2009 H1N1 "Swine Flu" pandemic). In contrast, influenza B can only infect humans and is less likely to ...

The U.S. winter virus season is in full force, and by one measure is the most intense in 15 years.

Cold and flu may seem alike, but knowing their key differences can prevent serious health risks. Learn how to recognize and ...

U.S. health officials recommend that everyone 6 months and older get an annual flu vaccination. About 44% of adults got flu ...