How do pandemic viruses occur?
New influenza viruses emerge as a result of a process called antigenic shift, which causes a sudden and major change in influenza A viruses. These changes occur when proteins on the surface of the virus combine in new ways as a result of mutation or exchange of genetic material between multiple influenza viruses. If such changes result in a new influenza A virus subtype that can infect humans and spread easily from person to person, an influenza pandemic can occur.
New influenza viruses occur as a result of a process called antigenic shift, which causes a sudden and major change in influenza viruses. These changes occur when proteins on the surface of the virus combine in new ways as a result of mutation or exchange of genetic material between multiple influenza viruses. These changes result in a new influenza virus subtype that infects humans and spread easily from person to person, an influenza pandemic occurs.
