Current seasonal influenza vaccines show good efficacy when they are well-matched with the circulating virus strains.
However, influenza viruses constantly change their surface glycoproteins that are the targets of most immune responses, allowing them to escape pre-existing immunity, a process called antigenic drift. Therefore, seasonal influenza vaccines have to be reformulated and re-administered on an annual basis. In addition, novel viruses can appear at irregular intervals and cause influenza virus pandemics that can claim millions of lives.
GSK Biologicals is now developing a new influenza vaccine that contains modified inactivated influenza viruses. The purpose of this approach is to elicit an immune response that would protect against all current and future circulating influenza strains without having to administer the vaccine each year.