DECLINING childhood vaccination rates in the US could lead to the resurgence of previously eliminated infectious diseases, with measles at greatest risk of becoming endemic within decades. This report examines the potential impact of reduced immunisation coverage on outbreak frequency and endemic reestablishment, using simulation models to project case numbers and complications under varying vaccination scenarios.
The study employed a simulation model parameterised with state-level demographic, immunity, and disease importation data (2004–2023) to estimate cases of measles, rubella, poliomyelitis, and diphtheria over 25 years. At current vaccination rates, measles is projected to become endemic in 83% of simulations (mean time: 20.9 years), causing 851,300 cases (95% UI: 381,300–1.3 million). A 10% decline in MMR vaccination could result in 11.1 million measles cases (95% UI: 10.1–12.1 million), while improving coverage by 5% would reduce cases to 5,800 (95% UI: 3,100–19,400). Under a hypothetical 50% vaccination decline, the model predicts 51.2 million measles cases (95% UI: 49.7–52.5 million), 9.9 million rubella cases (95% UI: 6.4–13.0 million), 4.3 million poliomyelitis cases (95% UI: 4–21.5 million), and 197 diphtheria cases (95% UI: 1–1,000), alongside 10.3 million hospitalisations and 159,200 deaths. Measles would likely become endemic within 4.9 years (95% UI: 4.3–5.6) under this scenario, followed by rubella (18.1 years) and poliomyelitis (19.6 years in 56% of simulations).
These findings highlight the critical need to maintain high childhood vaccination coverage to prevent avoidable outbreaks and endemic resurgence. Clinicians must advocate for routine immunisation, address vaccine hesitancy through education, and support public health measures to mitigate transmission risks. Future policies should prioritise equitable vaccine access and rapid outbreak containment strategies to avert long-term public health crises.
Reference
Kiang MV et al. Modeling reemergence of vaccine-eliminated infectious diseases under declining vaccination in the US. JAMA. 2025;DOI:10.1001/jama.2025.6495.
