VACCINE DEVELOPMENT TECHNOLOGIES FOR OLDER ADULTS AND INDIVIDUALS WITH UNDERLYING MEDICAL CONDITIONS

Abstract

Population aging is significantly increasing the burden of infectious diseases among older adults, particularly vaccine-preventable diseases such as influenza, herpes zoster, and respiratory syncytial virus (RSV). However, the effectiveness of conventional vaccines in this population is limited due to age-related immunosenescence. This study conducted a systematic narrative review to synthesize scientific evidence on disease burden and technological strategies in vaccine development for individuals aged ≥60 years. Through a structured search and screening process, a total of 21 relevant studies were included for analysis. The findings indicate that older adults experience substantially higher rates of hospitalization and mortality compared to younger populations, alongside a marked decline in vaccine-induced immune responses. Two primary technological approaches have been identified: increasing antigen dosage and the use of next-generation adjuvant systems. Among these, adjuvants such as MF59 and AS01 demonstrate significant improvements in both the magnitude and durability of immune responses. These findings highlight the urgent need to develop age-specific vaccines tailored for older adults in order to enhance disease prevention effectiveness in the context of global population aging.