WHO Backs Lower-Cost Maternal RSV Vaccine to Protect More Babies

WHO recommends giving RSVpreF during the third trimester, from the 28th week of pregnancy onwards, allowing enough time for protective antibodies to pass through the placenta before delivery.

The World Health Organization (WHO) has prequalified a multi-dose vial presentation of the maternal respiratory syncytial virus vaccine RSVpreF, sold under the name ABRYSVO®, opening the door to broader and more affordable protection for newborn babies. The new presentation is expected to make vaccine purchasing, storage and delivery easier, particularly in countries supported by Gavi, the Vaccine Alliance, where health systems must often serve large populations with limited resources.

WHO had prequalified the vaccine's single-dose presentation in March 2025, followed by Gavi's decision in July 2025 to establish a maternal RSV vaccination programme. Approval of the multi-dose option gives national health authorities a potentially more practical choice when planning large immunisation campaigns, since several doses can be supplied in one vial and administered through existing maternal healthcare services.

RSV takes its heaviest toll on the youngest infants

Respiratory syncytial virus is one of the world's leading causes of severe respiratory illness and pneumonia among young children, causing an estimated 3.6 million hospitalisations and about 100,000 deaths in children under five every year. Nearly half of these deaths occur among babies younger than six months, a period when infants are especially vulnerable because their immune systems are still developing and they may deteriorate rapidly after becoming infected.

The burden is deeply unequal, with around 97% of RSV deaths occurring in low- and middle-income countries where families may struggle to reach hospitals or gain access to oxygen, monitoring and other supportive care. Some children die at home before reaching a health facility, making prevention during the first months of life particularly important for communities living far from well-equipped medical services.

Vaccination during pregnancy passes protection to the baby

The maternal RSV vaccine works by stimulating the pregnant woman's immune system to produce antibodies, which are then transferred to her baby before birth and provide protection during the first six months of life. WHO recommends giving RSVpreF during the third trimester, from the 28th week of pregnancy onwards, allowing enough time for protective antibodies to pass through the placenta before delivery.

Developed with support from the Gates Foundation, the lower-cost multi-dose presentation could help countries introduce maternal RSV vaccination through routine antenatal and national immunisation programmes. Easier delivery may allow more pregnant women to receive the vaccine during scheduled health visits, giving their babies early protection without requiring an additional injection immediately after birth.

WHO recommends that every country add one of two RSV prevention options to its national programme: vaccination with RSVpreF during pregnancy or administration of the monoclonal antibody nirsevimab to infants. Countries can choose the approach that best fits their health services, available resources and local needs, while the new multi-dose vaccine presentation offers another path towards preventing severe illness, hospitalisation and avoidable deaths among the world's youngest children.