WHO Prequalifies Multi-Dose RSV Vaccine to Protect Infants Globally

The World Health Organization has granted prequalification status to the multi-dose vial presentation of the maternal respiratory syncytial virus vaccine, RSVpreF, marketed commercially as Abrysvo. The regulatory decision provides international procurement agencies and national health ministries with a substantially more affordable and logistically manageable option to protect young infants against severe lower respiratory tract disease during their initial months of life.

Developed with financial and technical support from the Gates Foundation, the multi-dose presentation is structured to significantly lower per-dose purchasing costs and reduce cold-chain storage space requirements for public healthcare networks. The approval builds directly upon the global health body's earlier prequalification of the vaccine's single-dose formulation in March 2025 and aligns with a July 2025 decision by Gavi, the Vaccine Alliance, to establish a dedicated funding program for maternal RSV immunization across low-income countries.

Respiratory syncytial virus, an RNA virus belonging to the Pneumoviridae family with A and B genotypes, represents one of the primary infectious hazards to early childhood survival worldwide. Epidemiological statistics compiled by health organizations indicate that RSV infections trigger more than 3.6 million hospital admissions and approximately 100,000 deaths annually among children under five years of age.

The lethal impact of the pathogen is overwhelmingly concentrated in the earliest stages of infancy. Nearly half of all fatal cases occur in infants younger than six months old, a delicate period when undeveloped immune systems can deteriorate rapidly following acute pulmonary infection. Furthermore, roughly 97 percent of global infant deaths caused by RSV occur in low- and middle-income nations where families face severe barriers accessing supportive medical interventions such as supplemental oxygen, intravenous hydration, and specialized clinical monitoring. In many impoverished regions, critically ill infants die at home before reaching a functional treatment facility.

The prevention mechanism behind RSVpreF relies on immunizing the mother to confer passive protection to the fetus before birth. When administered to a pregnant woman, the vaccine stimulates her immune system to produce high titers of protective antibodies. These maternal antibodies pass directly through the placental barrier, providing the newborn with circulating passive immunity that guards against severe lower respiratory illness and bronchiolitis throughout the first six months of life.

To achieve optimal antibody transfer, World Health Organization guidance specifies exact clinical timing for administration. The agency recommends giving the RSVpreF maternal vaccine during the third trimester of pregnancy, starting from the 28th week onwards. Administering the shot during this window allows sufficient time for maternal antibody synthesis and transplacental transfer prior to delivery, ensuring the newborn arrives with substantial immune defenses already in place.

While the initial prequalification of single-dose vials in early 2025 marked an important benchmark, single-use packaging presents notable operational challenges for lower-income health systems. Single-dose vials require substantial cold-chain refrigeration volume, create larger shipping burdens, and carry higher unit costs that complicate large-scale rollout across constrained public budgets.

The multi-dose vial presentation directly resolves these operational bottlenecks by supplying multiple doses within a single container. This format drastically cuts freight packaging, reduces space requirements in central medical stores, and allows primary health centers to deliver vaccinations through routine antenatal care visits. Healthcare workers can administer doses to pregnant women during standard prenatal appointments, avoiding the need for dedicated immunisation clinics or costly secondary newborn appointments.

The addition of the multi-dose option expands the operational choices available to governments as they establish national infant protection guidelines. World Health Organization policy framework urges all member states to incorporate a validated RSV prevention tool into their standard public health schedules, offering a choice between maternal vaccination with RSVpreF during pregnancy or the administration of the monoclonal antibody nirsevimab directly to newborn infants.

National health leaders can assess local health infrastructure, cold-chain capacity, and available financial resources to determine which delivery pathway best fits their domestic health systems. For many developing countries operating under Gavi financing, the multi-dose maternal vaccine offers an exceptionally efficient framework that utilizes existing maternal and child health visits to achieve broad population coverage without placing additional demands on neonatal care services.

Following formal WHO prequalification, international procurement agencies, Gavi, and domestic ministries of health are preparing to integrate the multi-dose formulation into upcoming pharmaceutical supply cycles. Implementation efforts will focus on establishing country-level supply lines, updating clinical training materials for antenatal workers, and finalizing national delivery protocols, with priority deployment directed toward high-burden countries in low- and middle-income regions.