RSV Protection for Babies: Pregnancy Vaccine or Antibody Shot?

The short answer: new figures from the UK show that, after the first full year of the maternal RSV (respiratory syncytial virus) vaccine programme, around 50% fewer babies under 6 months were admitted to intensive care with RSV¹. There are now two ways to protect a young baby: a vaccine for the mother during pregnancy, or a long-acting antibody injection for the baby after birth. Most babies need only one of them².

What does the latest data show?

Severe cases halved. The UK Health Security Agency (UKHSA) published its annual RSV report on 13 August 2026. In the 20 NHS trusts taking part in surveillance, 63 babies under 6 months were admitted to intensive care or high dependency units with confirmed RSV chest infection in winter 2025–26, compared with 131 the year before¹. Among women who gave birth between March 2025 and February 2026, 61.7% had received the vaccine¹.

Protection above 80%. On 17 April 2026, UKHSA released a study of nearly 300,000 babies, about 90% of all births in England during the period³:

When the mother was vaccinated at least 2 weeks before the birth, the baby's risk of hospital admission for RSV fell by 81.3%
With at least 4 weeks between vaccination and birth, protection reached nearly 85%
Even vaccination as close as 10–13 days before birth cut admissions by 50%
Premature babies were protected too, provided there were at least 2 weeks between vaccination and birth

Why does RSV matter so much for young babies?

RSV is common, and most children have had it by the age of 2. Usually it causes a mild, cold-like illness, but it can lead to bronchiolitis or pneumonia⁴. Figures from the US Centers for Disease Control and Prevention (CDC)⁴:

Two to three of every 100 infants under 3 months are hospitalised with RSV each year
Before RSV immunisations were introduced, RSV was the leading cause of infant hospitalisation in the United States, with an estimated 58,000–80,000 children under 5 hospitalised each year
The younger the child, the higher the risk. Babies born prematurely, children with chronic lung disease or congenital heart disease, and children with weakened immune systems are at greater risk

UKHSA adds that there is no risk-free birth month, but babies born in late summer or autumn are the most likely to be admitted to hospital with RSV¹.

Pregnancy vaccine or antibody shot: how do you choose?

The CDC recommends that every baby be protected by one of these two options²:

	Maternal RSV vaccine	Infant long-acting antibody
Who gets it	The pregnant woman	Babies under 8 months whose mothers were not vaccinated in pregnancy
How it works	The mother makes antibodies that cross the placenta	Antibodies are given directly to the baby
Timing in the US²	Weeks 32–36 of pregnancy, September to January in most areas	Shortly before RSV season, or within 1 week of birth for babies born during the season (October to March)
How long it lasts	About 6 months after birth	At least 5 months

A few additional points²:

It takes about 2 weeks after vaccination for the mother to develop antibodies and pass them to the baby
Two long-acting antibodies are currently available for infants, nirsevimab and clesrovimab
A small group of high-risk children aged 8–19 months can have a further dose of nirsevimab before their second RSV season, for example children born prematurely with chronic lung disease or those who are severely immunocompromised

Practice differs between countries. The NHS in the UK offers the vaccine from week 28, all year round, and recommends it in every pregnancy⁵. The US CDC does not currently recommend another dose in a later pregnancy, and advises an antibody for the baby after birth instead². Follow the arrangements where you live, and raise it yourself at an antenatal appointment. For what happens at each visit, see our prenatal checkup schedule.

Is the RSV vaccine safe in pregnancy?

The NHS says the most common side effects are mild and short-lived: swelling or pain at the injection site, a headache and an aching body. Studies have shown that having the vaccine in pregnancy is much safer than the risk of the baby getting RSV⁵. In its comparison table, the CDC also lists one possible risk that is still under study: hypertensive disorders of pregnancy, including pre-eclampsia². If you have high blood pressure or a related history, talk it through with your obstetric team.

The RSV vaccine can be given at the same appointment as the whooping cough and flu vaccines, but the NHS advises having each one as soon as it is offered rather than waiting to combine them⁵. For the flu vaccine, see our guide to flu vaccination for children and in pregnancy.

What are the symptoms, and when should you get help?

The CDC describes the early signs as a runny nose, eating or drinking less, and a cough that may progress to wheezing or difficulty breathing. The illness often becomes worse a few days in⁴. In babies under 6 months, the only signs may be⁴:

irritability or decreased activity
feeding less
pauses in breathing lasting more than 10 seconds

Many infants with RSV do not have a fever⁴, so temperature alone is not a reliable guide.

Seek medical attention if your child is having difficulty breathing, is not drinking enough, or is getting worse⁴.

Frequently asked questions

Can I still have the vaccine if I missed the recommended weeks? It depends where you live. In the UK the vaccine can be given right up until labour⁵, and UKHSA says it can still help when given around ten days before the birth, although longer is better¹. In the US, a baby whose mother was not vaccinated at weeks 32–36 can receive a long-acting antibody after birth².

If I had the vaccine in pregnancy, does my baby still need the antibody? Usually not. The CDC states that most babies do not need both².

My baby has already had RSV. Can they catch it again? Yes. The NHS notes that most people get RSV several times during their life⁵.

This article summarises public information from the UK's UKHSA and NHS and the US CDC. The availability of RSV vaccines and antibodies, and the eligible weeks of pregnancy and ages, vary between countries and regions, so follow the advice of your local health authority and your doctor. If your baby is struggling to breathe or feeding much less than usual, seek medical care immediately.

References

UK Health Security Agency. (2026, August 13). Newborn ICU admissions drop 50% in first full year of RSV maternal vaccine programme. GOV.UK. https://www.gov.uk/government/news/newborn-icu-admissions-drop-50-in-first-full-year-of-rsv-maternal-vaccine-programme ↩ ↩² ↩³ ↩⁴ ↩⁵
Centers for Disease Control and Prevention. (2025, August 18). Immunizations to protect infants. https://www.cdc.gov/rsv/vaccines/protect-infants.html ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸
UK Health Security Agency. (2026, April 17). RSV maternal vaccine cuts baby hospital admissions by up to 85%. GOV.UK. https://www.gov.uk/government/news/rsv-maternal-vaccine-cuts-baby-hospital-admissions-by-up-to-85 ↩
Centers for Disease Control and Prevention. (2026, February 20). RSV in infants and young children. https://www.cdc.gov/rsv/infants-young-children/index.html ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶
NHS. (2024, September 1). RSV vaccine. https://www.nhs.uk/vaccinations/rsv-vaccine/ ↩ ↩² ↩³ ↩⁴ ↩⁵