Pregnant mums who have the flu jab protect their baby from the bug for the first six months of their lives, a new study found.
Mums pass on the immunisation to their unborn baby reducing the chances of them getting seasonal influenza when they are at their most vulnerable .
The infants had a 70 per cent reduction in laboratory-confirmed flu cases and an 80 per cent reduction in being hospitalised because of flu compared to babies from unvaccinated mothers.
Health records also showed that 97 per cent of laboratory-confirmed flu cases occurred in infants whose mums were not immunised against the disease while pregnant.
Now scientists called for immunisation of all pregnant mothers to be made a priority.
Pregnant women and young infants are among those at highest risk for dying from flu but babies under six months cannot have the flu jab.
But children can develop a very high fever or complications such as bronchitis, pneumonia and painful middle ear infection and may need hospital treatment and very occasionally a child may die from flu.
Flu can be very serious for children with diabetes, asthma, heart disease or lung disease , as they are more at risk of developing serious complications.
The “flu jab” is available every year on the NHS to protect adults and children at risk of flu and its complications.
It is offered to pregnant women, the over 65s and children aged six months to two years.
It is the best protection available against an unpredictable virus that can cause unpleasant illness in children and severe illness and even death
It is not a 100 per cent guarantee those immunised will be flu-free, but if they do catch it the effects are likely to be milder and shorter-lived than it would otherwise have been.
Assistant professor of paediatrics Dr Julie Shakib said: “Babies cannot be immunised during their first six months, so they must rely on others for protection from the flu during that time.
“When pregnant women get the flu vaccine there are clear benefits for their infants.
“We just really hope more pregnant women get the vaccine.
“That’s the take-home message of the study.”
The study examined the medical records of 245,000 pregnant women and more than 249,000 infants for nine flu seasons from December 2005 through March 2014.
Approximately a tenth of the women, 23,383, reported being vaccinated while pregnant compared with 222,003 unvaccinated.
It found a stark differences between confirmed flu cases and children being admitted to hospital.
Of the 658 infants identified with laboratory-confirmed influenza, 638 cases or 97 per cent occurred in babies whose mums were not immunised.
Of these 151 were hospitalised and 148 were those born to unvaccinated mothers.
To confirm its findings scientists looked at cases of RSV (respiratory syncytial virus), a respiratory infection that also occurs in infants and young children during the winter months.
This found the vaccine had no effect on the incidence of RSV among infants, strengthening the findings that the benefits seen in the infants were actually due to the flu vaccine their mothers received.
The study published in published in Pediatrics online found in the US only half of pregnant women have the jab in the last flu season.
Vaccination rates in pregnant women averaged 10 per cent over the course of the nine flue seasons studied.
However, between June 2009 and September 2010, when the spread of the H1N1 flu reached pandemic levels worldwide, vaccination rates increased significantly as people became more aware of the risks of flu for pregnant women and their infants.
Professor Dr Michael Varner said: “Pregnant women are a high-risk group during influenza season and influenza outbreaks and should receive vaccinations.
“If their caregivers don’t offer them influenza vaccinations, I would encourage all pregnant women to ask them for it.”