At the surface, the immune response to a flu virus is simple. Some cells recognize the pathogen and send a signal to the immune system, and immune cells produce a potentially lifesaving antibody ...

While current flu vaccines provide protection against several strains of influenza A and B, the virus’s ability to evolve rapidly means that immunity may not always be sufficient.

Influenza A is believed to be the most severe type of flu virus for humans, although this is the subject of debate, as there is some evidence to suggest that influenza B might be equally as dangerous.

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.

New versions of the H5N1 virus are increasingly adept at spreading. Suggestions to either let it rip in poultry or vaccinate the birds could backfire.

Although the avian flu (H5N1) virus may not be making the news as frequently, it is still working hard behind the scenes, ...

As the Centers for Disease Control and Prevention (CDC) explains, bird flu is a disease caused by the influenza A virus. At the same time, recent CDC data shows that seasonal influenza A is rising ...

The flu is a contagious viral infection of the respiratory system that affects the nose, throat and lungs. It is caused by influenza viruses. Symptoms of mild flu infections can resemble those of ...

What we colloquially refer to as "the flu" is not just a single strain. "Influenza is a family of viruses — a group that has similarities in the way that their biology works," Dr. Stuart Ray ...

Two types of influenza viruses are responsible for seasonal flu outbreaks: Influenza A and B. Influenza A accounts for around 75 percent of all cases and tends to cause more severe illness in adults.

What’s the difference between flu A vs. flu B? The two most common and most severe flu strains are type A and type B, according to the CDC.Of the data collected so far this season, 96.6% of flu ...

Influenza activity is elevated across most of the country, with at least 5.3 million illnesses, 63,000 hospitalizations, and 2,700 deaths from flu so far this season, according to the CDC.