Vulnerable babies in Northern Ireland to receive first long-acting injection against RSV

Babies born very prematurely in Northern Ireland will, from this Autumn, be offered a new long-acting injection to protect against respiratory syncytial virus (RSV), a potentially life-threatening illness for young children.

The new medicine, Nirsevimab, replaces the current five-dose treatment, Palivizumab, and is expected to offer over 80% protection through a single injection lasting the entire RSV season from September to February.

The rollout follows updated advice from the Joint Committee on Vaccination and Immunisation (JCVI), which in February 2023 recommended introducing long-acting monoclonal immunisation for babies at high risk and those born too early to benefit from maternal RSV vaccination.

The new protection will be available to:

• High-risk infants, including those born before 32 weeks’ gestation

• Babies too premature to receive antibody protection via the maternal RSV vaccine currently offered to pregnant women in the UK

“Significant impact on our health service each year”

Welcoming the development, Health Minister Mike Nesbitt said:

“The risk of contracting RSV for children born very prematurely in their first winter is extremely serious and has a significant impact on our health service each year. My Department has approved using this new vaccine in line with the approach being taken across the other UK nations.

“This innovative vaccine further strengthens our winter preparedness to prevent avoidable hospital admissions and reduce pressures on GPs and Emergency Departments. It follows on from the launch of an RSV vaccination programme for pregnant women and adults aged 75-79 years old last year.

“I would encourage parents and guardians of those eligible to avail of the vaccination to help protect their baby from illness.”

Early signs of impact in 2025 data

Preliminary data suggests RSV-related hospital pressures may already be easing. In 2024, there were 1,218 unique RSV episodes and 823 hospital admissions among children aged 0–4 in Northern Ireland.

In contrast, by early July 2025, the figures had dropped sharply to just 213 unique RSV episodes and 134 admissions in the same age group.

While the 2025 season is still ongoing, this early data points to the potential benefits of increased RSV immunisation coverage, including maternal vaccination and the anticipated rollout of Nirsevimab this autumn.

“Vaccinations offer children the very best start in life”

Chief Medical Officer, Professor Sir Michael McBride, highlighted the urgency of the initiative in light of falling vaccination rates:

“RSV is a potentially serious virus, particularly for very young babies. Vaccinations have been extremely effective in eradicating diseases and protecting children and other vulnerable groups from serious illness and death.

“Worryingly, we are now seeing a decline in the uptake of childhood immunisations. Vaccinations offer children the very best start in life. Quite simply, if children aren’t vaccinated, they’re not protected.”

How Nirsevimab compares to Palivizumab

Nirsevimab and its predecessor Palivizumab are monoclonal antibodies—medications that deliver ready-made immune defences directly to babies. However, Nirsevimab only requires one injection, while Palivizumab requires up to five monthly doses.

• Nirsevimab protection rate: Over 80%

• Palivizumab protection rate: Around 55%

This not only offers stronger protection but also simplifies the process for families and the NHS.

Part of wider UK rollout

Following a deal brokered between NHS England, the UK Health Security Agency (UKHSA) and manufacturer Sanofi, the UK has secured a cost-effective commercial supply of Nirsevimab.

Around 9,000 infants across the UK are expected to benefit from the new RSV immunisation programme in or before their first RSV season.

RSV infects 90% of children by age two, and is one of the leading causes of infant hospitalisation in the UK, especially in the first year of life. In Northern Ireland, RSV-linked emergency hospital admissions are closely monitored through virology and hospital systems data.

RSV vaccination in pregnancy

Since September 2024, the NHS has also offered an RSV vaccine to pregnant women, designed to boost the mother’s antibodies so that protection is passed on to the baby in utero. However, babies born before this transfer can occur remain at risk, making the Nirsevimab rollout a crucial safety net for the most vulnerable.