Regular seasonal flu jabs also provide children with better protection against future flu pandemics, a study suggests.

Researchers found that children who receive years of the vaccines develop antibodies that give broader protection against new strains.

But this ability does not exist in adults, possibly because they have been repeatedly exposed to the virus through infection or vaccination.

The scientists suggest their findings could help in the development of a universal flu vaccine for children, who are especially vulnerable to serious complications such as pneumonia, dehydration and, in rare cases, death.

Matthew Miller, lead author of the study and associate professor at the Michael G DeGroote Institute for Infectious Disease Research at McMaster University in Canada, said: “Little is known about how seasonal flu vaccination impacts the immune responses in children, who are a major source of flu transmission and a very high-risk group.

“Understanding how seasonal vaccination and different vaccine formulations shape childhood immunity is critical for effective prevention.”

He added: “When we give adults vaccines, they make a very specific immune response against seasonal strains.

“Adults simply don’t generate immune responses to seasonal flu vaccines capable of protecting them from pandemic viruses like children can.”

In the study the researchers also compared two forms of vaccine – the conventional flu jab and a nasal spray vaccine.

They found that both worked equally well at generating broadly protective antibodies – good news for those who do not like needles.

Dr Miller said: “This is an important finding because it means we have flexibility in terms of the type of vaccines we can use to make a universal vaccine for children.

“We now know that children’s immune systems are much more flexible than adults’ when it comes to being able to teach them how to make these broadly protective responses.”

The researchers spent three years studying immune responses in children between the ages of six months and 17 years.

They found that as the children grew older they became less capable of producing broadly protective antibodies, because of their repeated exposure to flu, through infection or vaccination.

Although measures employed during Covid-19, such as social distancing and wearing face coverings, have reduced flu rates, Dr Miller warns flu could return and possibly in more severe forms.

The findings are published in Cell Reports Medicine.