Infants in low- and middle-income countries bear the greatest burden of deaths from respiratory syncytial virus, yet they face major barriers to access to preventative measures. Research by UMC Utrecht PhD candidate Jonne Terstappen, MD explores how affordable interventions, stronger maternal immunization services and simpler research methods could improve access. These findings highlight why accessibility must guide product development from the onset.
Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract infections in young children. Globally, RSV infection presents a significant health problem and burden to the healthcare system with nearly 2 percent (1 in 56) of all healthy term infants being admitted to hospital with RSV infection. In addition, RSV infection is responsible for >100,000 deaths each year among children <5 years of age. The vast majority of these deaths occur in low- and lower-middle-income countries (LMICs) due to the lack of high-quality healthcare.
The PhD thesis of Jonne Terstappen, MD (Department of Paediatric Infectious Diseases, UMC Utrecht) examines how prevention of RSV infection can meet the needs of resource-limited countries, focusing on affordability, local research capacity and healthcare infrastructure.
Field research by Terstappen and colleagues among healthcare professionals and community representatives in Soweto (South Africa) identified barriers such as vaccine hesitancy, limited staff knowledge, vaccine shortages and inadequate documentation. Participants proposed better staff training, outreach through trusted community voices and clear vaccination records to support timely vaccination and continuity of services.
In addition, it appeared that for antenatal care teams, introduction of maternal vaccines requires investment in staff, reliable supplies and clinic systems alongside patient information. The proposed strategies still need evaluation to establish their effect on uptake.
In an LMIC-setting, Terstappen investigated whether small dried blood samples could replace conventional serum samples in RSV antibody studies. In an adult phase 1 trial of a candidate monoclonal antibody, dried blood measurements closely matched serum results for drug concentrations and virus-neutralizing activity.
Furthermore, simpler sampling, storage and transport could reduce costs and facilitate infant trials in resource-limited settings. Successfully transferring a dried-blood RSV neutralization assay to a LMIC setting (Ghana) also strengthened local research capacity, supporting participation by countries whose populations should benefit from new preventive products.
Daily nose drops containing the monoclonal antibody palivizumab were investigated as a potentially affordable, non-invasive approach. However, a trial enrolling 268 preterm infants found no preventive effect against RSV infection. Pandemic-related disruption limited the efficacy analysis to 94 infants; adverse events were similar between groups.
A subsequent controlled infection study in 28 adults found no reduction in viral load, although symptomatic infections were less frequent. These findings do not support this intranasal regimen for infant RSV prevention.
Laboratory studies of a long-acting monoclonal candidate antibody (developed with LMICs in mind) showed in vitro a higher barrier to drug resistance than comparator antibodies (palivizumab and nirsevimab) as well as activity against diverse RSV strains. These findings support further development of this antibody.
Jonne Terstappen concludes: “RSV product development follows a typical ‘trickle-down’ approach designed for high-income settings. My thesis proposes equity-by-design: plan for access, simplify methods for low- and middle-income countries, and embed affordability early. Four recommendations underpin this framework: (1) shared scientific ownership with local partners, (2) investment in local capacity, (3) economic feasibility from the outset, and (4) alignment with community priorities. Equity should be a foundational principle of RSV immunization development, rather than an afterthought.”
Jonne Terstappen, MD (1995, Maastricht) defended her PhD thesis titled “Equity-by-design n RSV immunization development” on September 30, 2026 at Utrecht University. Supervisor was Prof. Louis Bont, MD PhD and co-supervisors were Natalie Mazur, MD PhD and Eveline Delemarre, MD PhD (all Department of Paediatric Infectious Diseases, UMC Utrecht). Jonne Terstappen works as a global health resident at the Department of Pediatrics at Jeroen Bosch Hospital in Den Bosch.
