Sloppy viruses
Influenza A viruses are sloppy when they copy themselves, meaning future generations of viruses contain genetic mistakes or 'mutations'.
Even a small change in the gene pool of an influenza A virus will mean your immune system won't recognise it, even if you had a jab for a similar virus in the past. That's why new vaccines are developed each year to protect people from the latest version of influenza A.
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Each year scientists identify new viral strains and develop vaccines to protect against them.
Image: Centre for Disease Control |
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