06 Jul 2019
Influenza season 2019 statement from the Doherty Institute
Influenza viruses mutate and evolve continuously in nature. This is why influenza vaccines have to be updated each year.
Among the four influenza viruses that cause seasonal influenza (influenza A (H1N1), A (H3N2) and the two types of influenza B viruses), influenza A viruses mutate more rapidly than influenza B viruses and A(H3N2) viruses mutate more rapidly than A(H1N1) viruses.
Influenza vaccines work by inducing an immune response and it is important to note that the vaccine can help the immune system to be effective against mutated viruses, depending on the type of mutation.
The WHO Collaborating Centre for Reference and Research on Influenza based at the Peter Doherty Institute for Infection and Immunity has confirmed that the A(H3N2) strain is different from last year. We don’t know yet how these changes will affect how the vaccine protects against it.
The vaccine effectiveness against A(H3N2) viruses has been poor for the last five years. However, the vaccine is effective against A(H1N1) and influenza B viruses.
The annual influenza vaccine provides the best protection against contracting influenza, and also reduces the severity of symptoms. We strongly encourage all Australians to have their flu vaccine this year.