43% of Brits have natural immunity against seasonal and pandemic flu

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Flu is one of the most common disease that affects lots of Britons, but a new study has a found that a whopping 43 per cent of people across England have natural immunity against both seasonal and pandemic influenza. The research also found that the immune cells that offered the protection also reduced the chances of shedding the virus by two thirds.

The research, wherein 1,414 unvaccinated people across England were studied, revealed that certain T cells, immune cells that fight infection, have the ability to control influenza infections by targeting a core structural protein called the nucleoprotein common to all strains of influenza A – the most common type of influenza and the only type capable of causing pandemics.

Researchers reveal that all strains of influenza A, including those that cross over from animals such as swine flu, have a very similar nucleoprotein structure which makes them vulnerable to such T cells.

For the research, scientists used data gathered every autumn through spring from 2006-2010, including the 2009 swine flu epidemic. The analysis of the data revealed that the flu-killing T cells, primed by exposure to flu earlier in life, were effective against both seasonal flu and swine flu, offering cross protection from symptoms and reducing shedding of virus from the nose.

Professor Andrew Hayward (UCL Farr Institute of Health Informations Research) said that all the current influenza vaccines are devised such that they help our immune system make antibodies that target the proteins on the outside of a flu virus. These proteins evolve over a period of time making the vaccines useless and increasing the risk of a pandemic making it hard for the public health community and vaccine manufacturers to keep up.

After the 2014 flu vaccine was found to protect against the wrong strain, the new finding offers the possibility of a universal vaccine to reliably reduce the severity and spread of all types of influenza A. The finding also helps to explain why so many people who catch flu never experience symptoms, even in a pandemic.

“This was illustrated last year, when the seasonal flu vaccine was much less effective than normal. It’s also why we don’t have vaccine available at the start of a flu pandemic when it would be most useful. Although a vaccine to boost flu-killing T cell responses would not prevent individuals from becoming infected in the first place, it would help to stop those who were infected getting ill and spreading the virus through coughs and sneezes”, said Professor Hayward who is also co-lead author of the paper.

The research was a collaborative effort of researchers from University College London, Oxford University and Public Health England and published in the American Journal of Respiratory and Critical Care Medicine.