A NEW vaccine which could prevent babies developing a virus that can cause deadly respiratory infections is being trialled by Southampton hospital doctors.

Respiratory syncytial virus (RSV) is a leading cause of serious lung inflammation in babies and can sometimes develop into pneumonia.

Although it can affect people of all ages, it often causes only mild cold-like symptoms in older children and young adults.

However, in babies under six months old it can lead to severe lung infections such as bronchiolitis and pneumonia – resulting in about 16,000 hospital admissions and 30 deaths a year among infants in the UK.

A spokesman for University Hospital Southampton (UHS), which is taking part in the worldwide trial, said: "During winter the virus can cause epidemics responsible for up to one in six hospital admissions in children under a year old and, long term, can lead to persistent wheeze and asthma."

The two-year trial, being funded by GlaxoSmithKline, will take place in 18 countries and involve 150 babies aged six to seven months, including 50 in Europe.

The vaccine used in the study – ChAd155-RSV – has been successfully tested in adults and is currently being trialled in toddlers aged 12 to 23 months who have previously had RSV.

Professor Saul Faust, director of the NIHR Southampton Clinical Research Facility, said: "RSV is a highly infectious respiratory virus which affects the airways and, while it often results in a simple cold for adults, it constitutes a real danger for young babies.

"This is because their airways are narrower and they struggle to fight against the infection, leaving them at risk of severe inflammation of the lungs and potentially the development of pneumonia."

Prof Faust, who is a consultant in paediatric immunology and infectious diseases at University Hospital Southampton, said the study marked "an important step" in the bid to tackle RSV.

He added: "Despite the prevalence of RSV infections in infants - more than 16,000 hospital admissions a year in the UK - there is currently no vaccine available to protect babies under a year old.

"It is vitally important we find a way to reduce the risk in this vulnerable patient group and this international study is an important step towards achieving that."