Waning immunity and the future of booster vaccination strategies in global vaccine programs post COVID-19.

The problem of waning immunity is a major global concern of vaccine programs, with immunity against diseases such as COVID-19 (reduction in efficacy by ~25% in six months), pertussis (waning in 4-12 y), and influenza (annual updates needed) expected to decrease with time. While boosters reduce serious results in high-risk categories, these effects are short-term (4-6 months) and encourage global imbalances, where low-income areas lag in primary vaccination (<2%). Computational models have shown that primary vaccination in underserved regions prevents ~60% of hospitalizations worldwide, surpassing booster-focused measures (~47%). To maintain protection, variant-responsive boosters, rapid booster-design pipelines, universal vaccine platforms (including pan-coronavirus vaccines), and equity-based solutions (decentralized production) need to be integrated. Aligning with frameworks like the Immunization Agenda 2030 of the World Health Organization, plans should balance the expansion of high-risk groups while broadening primary access, providing infrastructure investment, and real-time surveillance to address evolving pathogens and systemic disparities.