WHO prequalifies multi-dose vial of the maternal RSV vaccine, setting the stage for introduction

Respiratory syncytial virus (RSV) is the leading cause of severe respiratory infections and hospitalizations in infants and young children. The virus is so widespread that nearly all children contract it before two years of age, but there are stark disparities in mortality: 98 percent of pediatric RSV deaths occur in low- and middle-income economies, where many children never make it to the hospital.

In August 2026, the World Health Organization (WHO) prequalified the multi-dose vial presentation of maternal RSV vaccines, marking an important milestone on the path to broader introduction. Multi-dose vials can reduce storage, shipping, and packaging expenses while saving critical cold chain capacity, making them well suited for low- and middle-income markets.

Gavi, the Vaccine Alliance has committed to opening a funding window for an RSV maternal immunization program, which will support introduction of the vaccine in low- and middle-income countries (LMICs). With a product suitable for LMICs now available, now is the time for countries to begin exploring how they can introduce vaccines.

The maternal RSV vaccine helps protect babies when they are the most vulnerable. Given in pregnancy, the vaccine enhances a pregnant woman’s immunity and increases natural antibody transfer to the baby for protection that lasts through the first critical months after birth. WHO globally recommends RSV vaccination in the third trimester of pregnancy, as defined by local guidelines.

“RSV is a major cause of infant illness and death, especially in low-resource settings where some children never even reach care,” said Clint Pecenka, director of PATH’s RSV vaccine project. “Maternal vaccination offers a vital chance to reduce this burden—protecting babies early and easing the pressure on families and health systems.”

The RSV maternal vaccine has shown impressive results in clinical trials. A Phase 3 clinical study found that protection from the vaccine remains high through 6 months after birth, with 82 percent efficacy in the first 90 days and 70 percent over 180 days. These data tell us that the vaccine can help protect children during their first 6 months of life, when RSV poses the greatest threat to their health.

And real-world data from countries that have introduced the maternal RSV vaccine, like Argentina and Scotland, are emerging and showing high vaccine effectiveness, especially against severe disease.

Further, RSV imposes a substantial strain on health systems and households, causing millions of hospitalizations and placing a burden on parents and caregivers. Introducing maternal vaccines could not only keep children out of the hospital, but could also avert health care costs and free up resources for other health priorities.

“Our cost-of-delivery analyses in Kenya, Ghana, and Mozambique show that estimated costs of delivering new maternal vaccines such as for RSV are within the range of other routine childhood vaccine costs,” said Ranju Baral, a senior health economist at PATH. “Modeling studies also indicate that these vaccines can be cost-effective in many LMICs. In short, RSV vaccines are a smart investment in maternal and child health where needed most.”

With the multi-dose vial presentation of maternal RSV vaccines now prequalified, this is a key moment to prioritize planning for their roll out, especially given that RSV is a new disease target for many countries. As countries begin planning for RSV prevention, they’ll need to weigh the local impact of the disease, the cost and benefits of available products, and how well those products fit within their health systems. This process is already underway in some LMICs, and collaborative initiatives like the Maternal Immunization Readiness Network in Africa and Asia (MIRNA) are providing support.

Other key steps will include preparing delivery platforms via antenatal care and immunization programs, raising awareness among health care providers and communities, and ensuring systems are ready to monitor safety and effectiveness. Long-term success will also depend on workforce readiness and securing funding.

WHO, PATH, and other contributors have developed a suite of communications materials that cover RSV disease, new prevention tools, and delivery considerations. These tools can help support informed decision-making and implementation planning around RSV and relevant interventions. In addition, PATH’s RSV intervention cost calculator allows users to estimate costs of maternal RSV vaccine and mAb products available in the global market.

Maternal RSV vaccines have exciting potential to protect infants from a deadly threat—one that has for too long been overlooked. By setting the stage for introduction, we can ensure that countries are well equipped to implement this lifesaving intervention in the coming years.