A "game-changing" vaccine given to pregnant mums can dramatically reduce the risk of a life-threatening respiratory disease in their babies, according to new results from a late-stage clinical trial.
The vaccine, code-named RSVpreF, lowered the chances of severe illness from the Respiratory Syncytial Virus (RSV) by 82% in the first 90 days of life, and by 69% over the first six months.
RSV kills 100,000 children under the age of five each year worldwide, with 45,000 of them under six months old.
Pfizer, which makes the vaccine, plans to apply for the first regulatory approval by the end of 2022.
Annaliesa Anderson, senior vice president and chief scientific officer for vaccine research and development at the company, said: "We are thrilled by these data as this is the first-ever investigational vaccine shown to help protect newborns against severe RSV-related respiratory illness immediately at birth."
Around 7,400 women in 18 countries took part in the phase 3 clinical trial, receiving either the vaccine or a dummy jab in the late second or third trimester of pregnancy.
Mums given the vaccine passed on protection to their babies in the womb. There was no evidence of safety issues.
Most deaths from RSV are in low- and middle-income countries.
In the UK an average of 83 children die each year, with a further 29,000 admitted to hospital. Rates are rising this autumn as the virus bounces back from a quiet period caused by reduced socialising during the COVID pandemic.
Dr Chrissie Jones, Associate Professor in paediatric infectious diseases at the University of Southampton, said: "It is an absolute game-changer and of high global importance.
"If this vaccine is approved by regulatory agencies, this vaccine would have a substantial impact on admissions to hospital for RSV disease. It is highly important for the UK, but crucial for low- and middle-income countries."
RSV is a common childhood virus, causing symptoms similar to a heavy cold. In babies under six months old, it frequently results in bronchiolitis, an infection of the small airways in the lung that can make breathing harder.
Prof Jonathan Ball, from the University of Nottingham, said: "RSV causes an infection that can result in pneumonia and is particularly problematic in very young children.
"Previous attempts to use vaccines to protect them, especially during the first-year life, has proven difficult, so the news from Pfizer that their early clinical trial data suggests good protection against lung infection…is great news."
Pfizer released the results in a press release. It says it will submit full data for publication in a medical journal.