Having an older sibling could double a baby’s risk of flu, according to research.
Infants with one older brother or sister are over twice as likely to end up in hospital with the flu as only children, while those with more than one sibling are at three times the risk.
The findings came from a study of over 400,000 babies born in Scotland between October 2007 and April 2015Â by researchers at University College London and Great Ormond Street Children’s Hospital in London.
Babies born between July and December were also at greater risk of hospitalisation as they were typically younger during winter flu season.
Children are ‘effective spreaders’ of the flu virus, according to the researchers, putting small babies at a greater risk of infection.
As infants under six months cannot get the flu shot, the researchers are urging parents to get older siblings vaccinated.
“Flu can be a serious infection in very young children but at the moment there is no vaccine approved for babies under six months,” said lead researcher Dr Pia Hardelid.
“This means we need to look at other ways to minimise the risk of infection.
Women can’t help when their child is born, she added, but could help to prevent their babies getting the flu by having a flu shot while they’re pregnant.
“There is some evidence that maternal vaccination during pregnancy can protect young babies from flu infection.”
The study’s findings were reported today in the European Respiratory Journal.
