Breathing life into infant respiratory health

In September 2024, the World Health Organization (WHO) Strategic Advisory Group of Experts (SAGE) recommended that all countries introduce maternal vaccination and/or long-acting monoclonal antibodies (mAbs) for the prevention of severe respiratory syncytial virus (RSV) disease in young infants. The milestone is exciting progress on the road to global scale up and use for these new, lifesaving interventions.

The task now is to raise awareness, overcome barriers to introduction, and shorten the timeline for product availability and use in low- and middle-income markets where need is greatest.

In anticipation of these needs, PATH and our partners have long been working to develop tools and generate/compile evidence to support informed decision-making and implementation planning around RSV and relevant interventions.

Virtually everyone gets RSV at some point, usually by two years of age. RSV disease is often mild, like a cold, but can be severe (or deadly) for infants.

The virus causes more severe childhood respiratory infections each year than any other pathogen worldwide. It puts millions of children in the hospital, causes thousands of deaths, and strains health systems and livelihoods. RSV activity can be seasonal (usually temperate climates) and year-round (usually tropical/sub-tropical climates.)

Although any child can get severely ill due to RSV, the highest risk is before 6 months of age—when nearly half of all RSV child deaths occur.

The youngest are the most vulnerable because of the ease with which their small airways can be blocked. Serious complications include bronchiolitis, pneumonia, and long-term impacts on lung health. Current treatment is limited to supportive care—oxygen being among the key interventions. (Learn about PATH’s recent work in strengthening market access and use of oxygen generation plants.)

Also at higher risk are children living in socioeconomically disadvantaged areas where they’re less likely to have access to adequate medical care and are, therefore, far more likely to die from RSV than children living in high-income contexts.

This unacceptable disparity underscores the importance of ensuring global access to interventions that prevent severe RSV disease before it starts.

Both new RSV prevention interventions protect in the first six months of life and elicit passive immunity whereby a person is given antibodies rather than having to produce antibodies themselves—a powerful approach for protecting young infants, who have immature immune systems and need immediate, robust protection.

Maternal vaccine

The new maternal RSV vaccine is given during pregnancy in one dose. It enhances a pregnant individual’s immunity, leading to increased natural antibody transfer to the baby for protection in early life. This works just like other maternal vaccines in widespread use (e.g., for tetanus).

The maternal RSV vaccine is different from some other maternal vaccines because administration is recommended during a defined gestational age window during pregnancy to maximize infant protection (WHO SAGE-recommended in the third trimester of pregnancy, as defined in the local context).

Long-acting mAb

Mimicking the natural antibodies that our immune systems produce, mAbs are antibodies specifically engineered in laboratories to fend off a targeted disease. The new RSV mAb is given to an infant in one dose soon after birth or prior to/during the first RSV season, enabling immediate protection for months.

For over a decade, PATH has partnered to advance RSV prevention along the full vaccine development-to-delivery continuum. Most recently, we’ve been busy developing tools, generating new evidence, and compiling existing evidence to support the enabling environment for introduction.

New tools for advancing the RSV conversation

Despite its massive disease burden, RSV has long been under-recognized as a public health problem.

Recognizing that awareness gaps can be barriers to introduction, WHO and PATH developed the RSV Roadshow communications toolkit, which stakeholders around the world are using to raise awareness at global, regional, and country levels around RSV disease, new immunization products, and delivery considerations. The open access materials include an overview primer presentation (and fact sheet) complemented by nine modular slide decks that can be mixed and matched with the primer to dive deeper into key topics.

WHO, PATH, and the ReSViNET Foundation are also hosting a 2024/2025 monthly webinar series for audiences to learn and engage about RSV prevention.

Generating new evidence

In collaboration, we’re also generating original evidence to inform decision-making on RSV prevention and maternal/mAb immunization approaches more generally.

Our large portfolio of health economics studies in Argentina, Bangladesh, Cameroon, Ghana, Kenya, Mozambique, Nepal, Nigeria, and Vietnam is filling data gaps around a range of questions, including maternal vaccine/mAb cost-effectiveness and cost of delivery; RSV cost of illness; and the greater benefits of maternal immunization. The information is critical as countries and financing institutions like Gavi, the Vaccine Alliance consider vaccine programming options.

PATH is also evaluating delivery requirements in Ghana, Senegal, Tanzania, and Zambia to improve understanding of the decision-making drivers and potential challenges around maternal immunization implementation feasibility as countries consider adding new maternal vaccines to their public health agendas.

In related research, PATH and WHO are assessing how current ANC visit timing and reach aligns with gestational age windows needed to optimize new maternal vaccines (e.g., RSV) in Mozambique, Vietnam, and the Pan American Health Organization region.

Compiling and packaging existing evidence

PATH and WHO recently completed a landscape analysis of pregnancy registries in low- and middle-income countries to provide a fuller picture of new maternal vaccine adoption readiness and inform implementation planning. PATH and other experts also compiled existing evidence in a recent Lancet article on RSV prevention’s potential for protecting young children and a WHO value profile on RSV prevention interventions published in Vaccine.

RSV has too long been in the shadows, sickening and killing young children in the absence of effective interventions to prevent it on a broad scale. We are finally on the cusp of being able to change that.

With rollouts in the wealthiest countries well underway, shortening the timeline to introduction in low- and middle-income markets is of the utmost importance to ensure that children, no matter where they live, have a chance at better health.

Never has the world had more hope of addressing RSV than now. Help spread the word. Don’t let this chance pass us by.