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Why do we have a new flu jab every year?


In 1933, scientists at the National Institute for Medical Research discovered that flu was caused by a virus. Four years later, they showed that all flu viruses are not the same.

When early vaccine trials began, researchers grew flu in hens’ eggs (because viruses can only reproduce in living things). Their studies suggested each annual outbreak was caused by a different strain of the flu virus.

To keep pace, the Worldwide Influenza Centre opened in 1948. Researching, collecting and sharing information about active flu strains, the Centre enabled vaccine manufacturers to target jabs against the right strain every year.

Black and white photo of flu researchers
Worldwide Influenza Centre 




The Worldwide Influenza Centre is now located in the Francis Crick Institute, where it plays a critical role within a global surveillance system coordinated by the World Health Organization.

Centre researchers studying the physical structures of active flu strains are also advancing our understanding of COVID-19 variants.

Researcher wearing a blue lab coat and orange gloves handling test tubes.
Lab at the Francis Crick Institute