Why seasonal influenza vaccines are essential

Every year, people are encouraged to get an annual influenza (flu) vaccine.1 In some countries, vaccination is particularly recommended for healthcare professionals and certain populations who are more at risk of complications.1

In Germany, for example, an annual flu vaccine is recommended for people over the age of 60, pregnant women (from the second trimester), people living with chronic health conditions like diabetes, as well as healthcare professionals.2 However, for people outside of those groups, the vaccine is still available in pharmacies for anyone with statutory health insurance.3

But why do we need a new flu vaccine every year?

Seasonal vaccines help us keep up with constantly evolving viruses.

Annual vaccination is the most helpful measure available to governments and healthcare systems in their preparation for the annual surge in flu cases.4,5

Seasonal vaccinations are needed because the viruses that cause flu are constantly mutating.6 These mutations usually happen when a virus infects a person and starts to multiply.7 Each time a virus multiplies, there is a chance that it will mutate and cause new variant strains – so the more people that are infected, the more quickly a virus can evolve.8 Vaccine effectiveness against new variant flu strains may be reduced, meaning a new vaccine formulation is needed.6 So, just because you have been protected from the flu in previous years, it doesn’t mean you are still protected this year.1

What goes into creating seasonal vaccines?

The idea of constantly mutating viruses might be concerning, but the good news is, new variants of the flu are carefully tracked by a global team of scientists and public health experts.9

There are currently 149 National Influenza Centres (NICs) across the world which send thousands of viral specimens to the World Health Organization (WHO) vaccine composition committee.10 This committee then characterises the samples to predict which flu strains we will need protection from in the coming year. These strains are then used to develop seasonal flu vaccines.6

This is a similar process to how vaccines were developed to battle against the COVID-19 pandemic.11,12

Is flu still a health threat?

With up to 650,000 flu-related deaths globally every year13, influenza continues to be a serious disease for people at higher risk of flu complications (e.g., people over the age of 60 years, pregnant women, and people living with chronic health conditions).14

More Information

If you have any questions about the flu vaccine, or to learn more about the flu vaccine available to you, please speak to your doctor or healthcare professional.

Dirk Poelaert of Novavax
Dirk Poelaert, MD
Senior Director, Medical Affairs

Share this blog post on your social media.


  1. Influenza (Seasonal). WHO 2023. Available at https://www.who.int/news-room/fact-sheets/detail/influenza-(seasonal) [Accessed 7 Sept 2023].
  2. Current Data and Information on Infectious Diseases and Public Health: Epidemiologisches Bulletin. Robert Koch Institut 2023. https://www.rki.de/EN/Content/infections/Vaccination/recommandations/04_23_englisch.pdf?__blob=publicationFile [Accessed 7 Sept 2023].
  3. Steffen A, et al. Vaccines (Basel). 2021;9:485.
  4. CDC: Prevention Strategies for Seasonal Influenza in Healthcare Settings. Available at https://www.cdc.gov/flu/professionals/infectioncontrol/healthcaresettings.htm [Accessed 28 September 2023].
  5. Roles and Responsibilities in Preparedness and Response. Available at https://www.ncbi.nlm.nih.gov/books/NBK143067/ [Accessed 28 September 2023
  6. History of the Influenza Vaccine. WHO 2023. Available at https://www.who.int/news-room/spotlight/history-of-vaccination/history-of-influenza-vaccination [Accessed 7 Sept 2023].
  7. Why Viruses Mutate, Explained by an Infectious Disease Expert. UnityPoint Health 2023. Available at https://www.unitypoint.org/news-and-articles/why-viruses-mutate-explained-by-an-infectious-disease-expert#:~:text=Once%20a%20virus%20enters%20your,varies%20from%20virus%20to%20virus [Accessed 7 Sept 2023].
  8. Drake JW, Holland JJ. Proc Natl Acad Sci USA. 1999;96:13910–13913.
  9. Ziegler T, et al. Lancet. 2022;400:981–982.
  10. Brydak LB. Reumatologia 2023;61(3):149-151
  11. Tracking SARS-CoV-2 Variants. WHO 2023. Available at https://www.who.int/activities/tracking-SARS-CoV-2-variants [Accessed 7 Sept 2023].
  12. Guidance. A Guide to the COVID-19 Spring Booster 2023. UK Health Security Agency 2023. Available at https://www.gov.uk/government/publications/covid-19-vaccination-spring-booster-resources/a-guide-to-the-covid-19-spring-booster-2023#:~:text=You%20will%20be%20given%20a,be%20advised%20by%20your%20doctor [Accessed 7 Sept 2023].
  13. WHO Launches New Global Influenza Strategy. WHO 2019. Available at: https://www.who.int/news/item/11-03-2019-who-launches-new-global-influenza-strategy [Last accessed 7 Sept 2023].
  14. CDC: Flu Symptoms & Complications. Available at https://www.cdc.gov/flu/symptoms/symptoms.htm [Accessed: 28 September 2023].