Two doses of influenza vaccine during a single flu season

 Statement date: 24 April 2020

Background: 

• All Australians are encouraged to get the influenza vaccine this year (2020). 
• The timing for starting influenza vaccination has been brought forward. The rationale is to:
  • ensure that vulnerable groups are covered before influenza arrives
  • reduce the burden on GPs and hospitals at a time when COVID is placing considerable demands on the health care system
  • avoid having to manage large number of cases of influenza and COVID at the same time

Position: 

• The influenza vaccine, especially against the H3 strain, tends to lose some effectiveness (around 6-8% per month) after 3-4 months. 
• The enhanced flu vaccine, recommended to those 65 years and older, was specifically designed (and demonstrated) to improve the effectiveness against the H3 strain of the influenza vaccine
• There is no evidence that two doses of the influenza vaccine will provide either stronger or longer protection against influenza
• There is some evidence that the enhanced vaccine available to those 65 years and older does provide better protection against hospitalisation from getting influenza.
• There is limited evidence that the duration of protection against influenza is longer when the older person receives an enhanced influenza vaccine.