WHO clears a multi-dose maternal RSV vaccine vial to widen access in poor countries

The World Health Organization has prequalified a multi-dose vial version of the maternal respiratory syncytial virus vaccine RSVpreF (Abrysvo), a step aimed at getting the vaccine into the countries where nearly all RSV deaths happen [s1]. The news is about logistics and price, not a new efficacy result: prequalification signals that WHO judges a product's quality, safety and suitability for the markets its procurement partners serve, and the multi-dose format is designed to be cheaper and easier to deliver at scale [s1].

RSV is a leading cause of infant respiratory illness worldwide. WHO estimates it causes more than 3.6 million hospitalisations and about 100,000 deaths a year among children under five, with almost half of those deaths in infants younger than six months — the group a maternal vaccine is meant to protect [s1]. Roughly 97% of RSV deaths occur in low- and middle-income countries, where supportive hospital care is limited and, WHO notes, children sometimes die at home before reaching a facility [s1]. That geography is the whole point of the prequalification: the burden is concentrated exactly where affordability and cold-chain-friendly packaging decide whether a vaccine actually reaches people.

Why a vial format is the news

A maternal RSV vaccine works by immunising a pregnant woman so that her antibodies cross the placenta and protect the baby through its first months of life; WHO recommends giving RSVpreF in the third trimester, from week 28 onwards, to maximise that transfer [s1]. The vaccine itself is not new — WHO prequalified a single-dose presentation in March 2025, and Gavi, the Vaccine Alliance, decided in July 2025 to establish a maternal RSV vaccine programme [s1]. What changed now is the presentation: a lower-cost multi-dose vial, developed with support from the Gates Foundation, that WHO says makes it more feasible for countries to plan and run large introductions [s1].

Multi-dose vials cut per-dose cost and storage volume, which matters for national programmes operating on tight budgets — the trade-offs (open-vial wastage, careful handling) are the familiar ones of vaccine logistics rather than anything specific to this product. The stakes are set by where the deaths fall: WHO notes that in many cases children in low- and middle-income countries die at home, before reaching a health facility, which makes prevention through maternal immunisation more consequential than in settings where hospital care can rescue a severe case [s1]. Reaching pregnant women at scale, in the third trimester, is a delivery problem that a cheaper, higher-count vial is meant to ease rather than solve outright.

Where it fits

WHO recommends that every country introduce one of two options against infant RSV: the maternal vaccine RSVpreF, or nirsevimab, a monoclonal antibody given to the infant directly [s1]. The prequalification does not settle which a given country should choose; it lowers a practical barrier to the maternal route. Real-world data on that route is beginning to accumulate — Argentina's programme, for instance, cut infant hospitalisations in its first season, and broader season reviews continue to track how well RSV immunisation holds up.

The gap this addresses is a familiar one in global health: a vaccine can exist, be effective, and still not reach the children who need it most because the version on the market is priced and packaged for wealthy health systems. Whether the multi-dose vial translates into actual coverage now depends on financing, national decisions and delivery — the same chain that governs childhood vaccination coverage generally — not on the prequalification alone.

Sources

• [s1] WHO prequalifies multi-dose RSV vaccine vial, paving the way to protecting more infants globally, World Health Organization, 9 September 2026.