Infants could soon be given a vaccine that slashes their risk of falling ill with respiratory syncytial virus (RSV), scientists announced last night. 

A jab made by AstraZeneca and French firm Sanofi was found to cut hospitalisations by two-thirds in children under the age of one.

The nirsevimab vaccine is given as a single dose and protection lasts for five months – a full RSV season.

Results of the phase three trials have been described as a ‘paradigm shift’ by experts running the studies.

No vaccine for the condition currently exists for the general population, despite decades of research.

An injection known as palivizumab is offered to high-risk infants in the UK but it only provides one month of protection, meaning infants need five jabs to cover a season.

RSV causes coronavirus-like symptoms and is one of the leading causes of admission among infants in the UK.   

It accounts for 29,000 hospitalisations and 80 deaths among children under five in the UK per year, and 58,000 admissions and 500 fatalities in youngsters in the US.

Infants could soon be given a vaccine that slashes their risk of falling ill with respiratory syncytial virus (stock)

The nirsevimab vaccine was 74.5 per cent effective at stopping children from getting ill enough with RSV to need medical attention. The graphs show the proportion of vaccinated children who did not seek any medical care due to an RSV virus (yellow), compared to the unvaccinated (blue). The internal graph shows the same data, but on a larger vertical axis 

Phase three clinical trials of the RSV vaccine recruited 1,490 healthy children in the US and South Africa who were aged one year or younger and entering their first RSV season, which runs from October to March in the UK.

Two-thirds of the infants were given the nirsevimab vaccine, while a third were given a placebo jab.

Nirsevimab is a long-acting monoclonal antibody vaccine, which involves injecting proteins that have been primed in a lab to fight the virus already. 

It does not require the activation of the immune system, which can take weeks with normal vaccines, offering rapid and direct protection against disease.

The results, published in the New England Journal of Medicine, show 12 infants (1.2 per cent) who were given the vaccine required medical care due to respiratory viruses caused by RSV.

Meanwhile, 25 children (5 per cent) in the unvaccinated group needed to see a doctor, four times more than the jabbed cohort.

Hospital admission rates were nearly three times higher among the unvaccinated group (1.6 per cent) compared to the immunised children (0.6 per cent). 

Researchers at the Stanley Manne Children’s Research Institute in Chicago who are running the trials said the findings show the jab is 74.5 per cent effective at preventing hospitalisation among youngsters. 

Around a year after being recruited into the trial, 6.1 per cent of vaccinated children had RSV antibodies, compared to 1.1 per cent of unjabbed youngsters.

Side effects were recorded among 6.8 per cent of those who received the nirsevimab vaccine and 7.3 per cent of those who had the placebo, but most were mild or moderate, including pain at the injection site.

The fact the rates of side effects were roughly the same meant the vaccine was safe.

Dr William Muller, lead investigator of the study and scientific director of clinical trials at the institute, said: ‘These exciting data show that nirsevimab has the potential to offer RSV protection for all infants, which would be a paradigm shift in the approach to this disease.

‘We know that RSV has seen a resurgence with the easing of Covid public health measures. 

This shows us a broad immunisation approach is needed to help mitigate the substantial global burden RSV places on infants, their families and healthcare services.’ 

Source: DailyMail