Protection Invented, Not Delivered

Respiratory syncytial virus causes 33 million lower respiratory tract infections, 3.2 million hospitalizations, and approximately 100,000 deaths per year in children under five — 97-99% of those deaths in low- and middle-income countries. In 2023-2025, effective prevention tools reached high-income country markets: nirsevimab (a long-acting monoclonal antibody reducing RSV ICU admissions by 80%) and Abrysvo (a maternal vaccine with 82% efficacy in the first 90 days). In France and Spain, nirsevimab rollout to 80% of newborns reduced RSV hospitalizations by 70-90%. But nirsevimab costs ~$445/dose in the US, while Gavi's typical price point for LMIC procurement is ~$5/dose. WHO prequalified Abrysvo in March 2025, but the earliest projected LMIC access via Gavi is 2027 — meaning the children dying today from RSV will not benefit from products that already exist.

More than two-thirds of RSV deaths in LMICs occur outside a health facility — children die before reaching care. 88% of RSV hospital admissions occur in LMICs. Nearly half of all RSV hospitalizations and deaths affect infants under 6 months, the age group most amenable to maternal vaccination or birth-dose monoclonal antibody approaches. The technical problem (preventing RSV disease) has been solved; the remaining barrier is purely access, economics, and delivery — making this a paradigm case of the implementation gap between HIC and LMIC global health.

Palivizumab (the first RSV monoclonal antibody, approved 1998) required monthly injections at ~$1,500/dose per season — never feasible for LMICs. Nirsevimab solved the dosing problem (single injection, 5+ months of protection) but not the cost problem. Monoclonal antibodies are inherently more expensive to manufacture than vaccines, and economies of scale apply less strongly. Maternal RSV vaccines face delivery challenges: pregnant women in many LMIC settings have limited antenatal care contacts, and introducing a new maternal vaccine requires health system integration that takes years. WHO SAGE recommended both approaches in September 2024, but the pathway from recommendation to country-level implementation involves regulatory approval, Gavi investment decisions, procurement negotiations, cold chain capacity, and healthcare worker training — a cascade that adds years of delay.

Three parallel tracks could accelerate access: (1) a multi-dose vial formulation of Abrysvo, under development with Gates Foundation support (potentially available by 2026), would reduce per-dose manufacturing and distribution costs; (2) the Medicines Patent Pool has placed clesrovimab (a second RSV mAb) on its priority list, signaling potential voluntary licensing for LMIC manufacturers; and (3) Gavi's Board decision on an RSV vaccine investment case is expected in 2025. A student contribution could address the delivery optimization challenge: modeling which combination of maternal vaccination and infant mAb deployment maximizes RSV mortality reduction under realistic LMIC health system constraints.

A team could build a decision-analytic model comparing three RSV prevention strategies in a representative LMIC setting (e.g., Kenya or Mozambique): maternal vaccination only, birth-dose nirsevimab only, and a combined approach — evaluating cost-effectiveness under varying assumptions about antenatal care coverage, birth-dose delivery rates, cold chain capacity, and product pricing. Existing cost-of-delivery data from Kenya, Ghana, and Mozambique could inform realistic assumptions. Alternatively, a team could analyze the thermal stability requirements for mAb delivery outside the cold chain, evaluating whether controlled-temperature-chain protocols (allowing limited time outside 2-8 degrees C) could extend reach in last-mile settings. Relevant disciplines: health economics, epidemiology, operations research, immunology.