Body ‘remembers’ its first strain of flu

Catching flu is like riding a bike, researchers suggest. The body always remembers tackling its first case.

Children who contract a virulent strain of the disease develop a form of immunity to the virus, scientists say.

Catching flu is like riding a bike, researchers suggest. The body ­always remembers tackling its first case.

Children who contract a virulent strain of the disease develop a form of immunity to the virus, scientists say. If the first bug youngsters catch is a mild strain, however, they will be left vulnerable to vigorous germs.

While the body develops a strong immune response to the first strain it encounters, the reaction to further and subsequent ­viruses becomes weaker. The ­researchers analysed data from the Arizona Department of Health Services to determine ­reactions to the same flu strain.

They examined whether the body retained a memory of the first strain it was exposed to in a phenomenon called “immunological imprinting”. The medics tracked cases of flu to assess how strains affected people at different ages.

The study, published in the journal PLOS Pathogens, said two subtypes of the viruses H3N2 and H1N1 were responsible for most recent flu outbreaks.

They said that H3N2 caused the most severe cases, while H1N1 caused fewer deaths and was more common among young and middle-aged people.

The Times