RSV Vaccines and Treatments Face Global Access Hurdles

Almost 70 years after the discovery of the respiratory syncytial virus (RSV), vaccines and preventive treatments are giving babies a chance to beat the potentially deadly childhood infection.

As doctors turn to monoclonal antibody therapies and governments plan vaccination programs, clinical researchers are asking whether these measures will reduce the spread of the virus. Will fewer babies die from RSV, and fewer children develop permanent wheezing?

Recent studies offer clues.

Fabio Midulla, an associate professor of pediatrics at Sapienza University of Rome in Rome, Italy, said that the pharmaceutical industry is poised to push governments to use vaccines and monoclonal antibodies for even more children. “Such a push might work,” he said at the European Respiratory Society (ERS) 2024 Congress, “given that several studies have already demonstrated that their use can improve outcomes for children who do become infected and reduce societal costs by reducing hospitalizations.”

But Mariëlle WH Pijnenburg, a pulmonary specialist at Erasmus University Rotterdam in Rotterdam, the Netherlands, said at the Congress that greater rollout would require governments to force industry to lower prices. If treatments remain beyond the reach of lower-income countries — where the burden of RSV is the greatest — the death toll from this common childhood infection will remain stubbornly high, and the prospect of global elimination will remain forever out of reach, she said.

New Tools in the Fight Against RSV

Nirsevimab, a long-acting monoclonal antibody given to newborns to prevent severe infection, was approved by the European Medicines Agency (EMA) in October 2022 and the US Food and Drug Administration (FDA) in July 2023. And Abrysvo, a vaccine given to older adults and pregnant women to stop them from passing the virus to babies from birth through 6 months of age, was approved by the FDA and the EMA in 2023.

RSV is responsible for over 33 million lung infections in children younger than 5 years annually, with more than 4 million hospitalizations and nearly 200,000 deaths. According to the Centers for Disease Control and Prevention, every year, 2.1 million children younger than 5 years old visit a healthcare provider because of an RSV infection and between 58,000 and 80,000 children younger than 5 years old are hospitalized in the United States. The burden of severe RSV disease is also high among adults, with an estimated 123,000-193,000 hospitalizations, 24,400-34,900 ICU admissions, and 4680-8620 in-hospital deaths occurring annually among US adults.

While the virus affects all age groups, it is particularly severe in infants, swelling their airways and causing them to struggle for breath. Infection in infancy can lead to later complications, such as the development of wheezing, a condition that causes breathlessness and a feeling of tightening in the chest, and possibly also asthma.

Studies have shown that children and preterm infants infected with RSV who were given monoclonal antibodies experienced less post-infection wheezing, suggesting that RSV prophylaxis could prevent the development of wheezing bronchitis.

A study conducted in Galicia, Spain, showed that only 0.3% of infants who received prophylaxis with Nirsevimab were hospitalized for RSV-related lower respiratory tract infections. “This is very promising,” Yvonne Maldonado, MD, professor of pediatrics and epidemiology and population health at Stanford University in Stanford, California, told Medscape Medical News. “But this virus is ubiquitous. It’s found everywhere. It comes around every winter season. And immunity is not long-lasting.”

Older children who are not receiving monoclonal antibodies still experience RSV-related hospitalizations, suggesting the virus continues to circulate at high enough levels in the community. “The vaccine and monoclonal antibodies can reduce the risk of hospitalization and more severe disease in young kids, but they won’t eliminate the virus,” Maldonado said. “Right now, the goal is to prevent serious infection, not to prevent the spread of the virus completely.”

Expanding Access to RSV Prevention in Low-Income Countries

Currently, the RSV vaccine and monoclonal antibodies are only given in the United States, Europe, United Kingdom, and Canada to newborns, children at risk for severe disease, and pregnant women. However, Midulla said that pharmaceutical companies are pushing to broaden the rollout to a broader population within these countries. Yet, he said, over 99% of RSV infection–related deaths occur in the Global South.

No pharmaceutical company has sought approval in low-income countries such as those in Africa. “Unless they see there being a market in a country, they’re not going to go through the onerous process of getting [a vaccine] licensed,” Shabir Madhi, the dean of the faculty of health sciences and a professor of vaccinology at the University of the Witwatersrand, Johannesburg, South Africa, told Medscape Medical News.

He highlighted that almost 50% of RSV-related deaths occur in African children younger than 5 years, despite these children comprising just one fifth of the global under-5 population. The high burden of RSV mortality in the Global South is mainly due to poor access to healthcare and supportive treatments, such as supplemental oxygen, which can help children recover from severe RSV infection.

Companies are unlikely to pursue regulatory approval and licensing in low- and middle-income countries until GAVI, the global vaccine alliance, commits to procuring and funding the vaccines for these regions. GAVI’s decision would provide the necessary market incentive for manufacturers to seek approval.

Madhi suggested that GAVI’s decision on RSV vaccine procurement is imminent, likely early next year, following the World Health Organization’s Strategic Advisory Group of Experts on Immunization recommendation to vaccinate all pregnant women with the RSV vaccine, regardless of whether they are in high-income or low-income countries.

Nevertheless, even if vaccines become available, many African countries may still struggle to afford them. Madhi said that these countries would likely depend on GAVI and organizations like UNICEF to procure the vaccines at affordable prices. “The unfortunate reality is that many countries — especially in Africa — still wouldn’t be able to afford it, even if the vaccine cost as little as $5,” said Madhi. “But that’s where they would have the greatest impact.”

Midulla, Pijnenburg reported no relevant financial relationships.Madhi’s research unit, the Vaccines and Infectious Disease Analytics Unit, was involved in the clinical trials for the Pfizer RSV vaccine, the GSK RSV vaccine (which was terminated), as well as the MEDLEY trial of palivizumab. All funding for these studies went to his institution, the University of the Witwatersrand. Maldonado was Stanford principal investigator for the Pfizer RSV vaccine.

Manuela Callari is a freelance science journalist specializing in human and planetary health. Her words have been published in The Medical Republic, Rare Disease Advisor, The Guardian, MIT Technology Review, and others.