From profit to impact: lives saved and the future of RSV vaccine development.

Over the past 10 years, respiratory syncytial virus (RSV) has increasingly been recognised as a global health problem by international organizations such as the World Health Organization and the Bill & Melinda Gates Foundation. Nearly 2% (1 in 56) of healthy term infants are admitted to hospital with RSV in their first year of life, representing a substantial burden on health-care systems. 1 Wildenbeest JG Billard MN Zuurbier RP et al. The burden of respiratory syncytial virus in healthy term-born infants in Europe: a prospective birth cohort study. Lancet Respir Med. 2023; 11: 341-353 Summary Full Text Full Text PDF PubMed Scopus (12) Google Scholar However, RSV-related mortality is low in high-income countries (HICs), probably due to the availability of advanced respiratory support. More than 97% of RSV-related mortality occurs in low-income and lower-middle-income countries (LMICs), illustrating the inequitable distribution of the global burden of life-threatening RSV. The high mortality burden in LMICs (second to malaria) has been the basis for increased attention from major global health organisations. Meanwhile, further research has shown that the full burden of life-threatening RSV was previously greatly underestimated because estimates were largely based on in-hospital RSV surveillance. More than half of RSV-related deaths occur outside of the hospital. 2 Srikantiah P Vora P Klugman KP Assessing the full burden of respiratory syncytial virus in young infants in low- and middle-income countries: the importance of community mortality studies. Clin Infect Dis. 2021; 73: S177-S179 Crossref PubMed Scopus (16) Google Scholar Global data sharing efforts have allowed characterisation of children dying in the community compared with in hospital to understand potential global vaccine impact. 3 Mazur NI Löwensteyn YN Willemsen JE et al. Global respiratory syncytial virus-related infant community deaths. Clin Infect Dis. 2021; 73: S229-S237 Crossref PubMed Scopus (16) Google Scholar Recent global burden estimates are high: 3·6 million hospital admissions due to RSV-associated acute lower respiratory infection among children younger than 5 years annually. Although historically RSV has been portrayed as a paediatric disease, increasing evidence shows that RSV is an important cause of morbidity and mortality in older adults (≥65 years). 4 Falsey AR Hennessey PA Formica MA Cox C Walsh EE Respiratory syncytial virus infection in elderly and high-risk adults. N Engl J Med. 2005; 352: 1749-1759 Crossref PubMed Scopus (1448) Google Scholar The burden of RSV in older adults is similar to that of influenza; 4–10% of adults at high risk will develop acute RSV respiratory tract infection annually. 4 Falsey AR Hennessey PA Formica MA Cox C Walsh EE Respiratory syncytial virus infection in elderly and high-risk adults. N Engl J Med. 2005; 352: 1749-1759 Crossref PubMed Scopus (1448) Google Scholar