The resulting rapid change in viral genetics produces antigenic shifts, which are sudden changes from one antigen to another.

Type A influenza also undergoes infrequent and sudden changes, called antigenic shift.

"If there's a small antigenic shift, a point or two, it's only the flu," she corrected him.

Approximately every ten years, there's a major antigenic shift with epidemic potential, so it may have originated with Badri.

One increasingly worrying situation is the possible antigenic shift between avian influenza and human influenza.

This antigenic shift could cause the formation of a highly virulent virus.

One of the main reasons that any Influenza A virus is so deadly is because of antigenic shift.

Even more frightening, the A viruses periodically experience an antigenic shift.

When antigenic shifts occur, large numbers of people have no antibodies to protect them against the virus, causing a pandemic.

Widespread outbreaks of the flu usually follow significant changes (called antigenic shifts) in the virus and occur about every 10 years.