Paediatric Conditions16 September 2026

The new era of RSV prevention for infants

For decades, protection against respiratory syncytial virus was reserved for the highest-risk babies. Long-acting antibodies and maternal vaccines have changed that.

By NextGenHealth Editorial Team2 min read

A medical team attending to a newborn baby in hospital — Photo: Navy Medicine / Unsplash

In brief

Nirsevimab, clesrovimab and maternal RSV vaccines are transforming infant RSV prevention. How they work and how health systems choose between them.

RSV is a leading cause of hospital admission in infants.
Long-acting monoclonal antibodies can protect a baby through a whole season with one dose.
Maternal vaccination in late pregnancy offers another route to protecting newborns.

Respiratory syncytial virus (RSV) infects almost all children by the age of two. Most cases are mild, but RSV is one of the leading causes of hospital admission in infants, particularly in the first months of life, and every winter it fills paediatric wards.

The old approach

For around 25 years, the only preventive option was palivizumab, a monoclonal antibody that had to be injected monthly through the RSV season. Its cost and dosing schedule restricted it to babies at highest risk, such as those born very prematurely or with certain heart and lung conditions. Most infants admitted with RSV were born healthy and at term, and they had no protection.

Long-acting antibodies

Nirsevimab changed that. Engineered to last much longer in the body, it protects through a typical RSV season with a single injection. It was approved in the EU in late 2022 and in the US in 2023 for all infants entering their first RSV season. A second long-acting antibody, clesrovimab, was approved in the US in 2025.

Several countries that rolled out nirsevimab broadly reported substantial falls in infant RSV hospital admissions in their first seasons of use.

Maternal vaccination

The other route is to vaccinate the mother. An RSV vaccine given in late pregnancy prompts antibodies that cross the placenta and protect the baby for its first months. It was approved in the US in 2023 for use between 32 and 36 weeks of pregnancy, and the UK introduced a maternal RSV vaccination programme in 2024.

Choosing between them

Health systems are now deciding how to combine the two approaches: which babies should receive an antibody, whether maternal vaccination makes it unnecessary, and how to reach families who miss antenatal care. Supply, cost and uptake are the practical constraints. The scientific question of whether infant RSV can be prevented at scale has largely been answered.

RSV
Monoclonal antibodies
Maternal vaccination
Infectious disease

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