EFFECTIVENESS OF VACCINATION PROGRAMS IN REDUCING INFECTIOUS DISEASE PREVALENCE: A SYSTEMATIC REVIEW

Abstract

Background: Vaccination programs represent one of the most successful public health interventions for controlling infectious diseases. Despite their proven efficacy, questions remain about real-world effectiveness across diverse populations and settings.

Objective: To systematically evaluate the effectiveness of vaccination programs in reducing infectious disease prevalence, incidence, morbidity, and mortality across different vaccines, populations, and geographic contexts.

Methods: A systematic review was conducted in accordance with PRISMA 2020 guidelines. Searches were performed in PubMed/MEDLINE, Embase, Cochrane Library, and Web of Science for studies published between January 2001 and January 2024. Eligible studies reported empirical data on population-level vaccine effectiveness or impact, using observational or registry-linked designs. Data extraction captured study characteristics, vaccine type, coverage rates, and effectiveness outcomes. Quality was assessed using the Newcastle–Ottawa Scale, STROBE, or AMSTAR-2 as appropriate. Due to heterogeneity, results were synthesized narratively.

Results: Twenty-one studies met inclusion criteria, encompassing diverse methodologies including cohort studies, population-based analyses, and systematic reviews. Vaccine effectiveness was consistently high across programs: pertussis (96.2-100%), varicella (55-98% depending on doses), rotavirus (87% reduction in hospitalizations), HPV (83.9% reduction in cervical cancer), and measles (50% reduction in low-income countries). Maternal pertussis vaccination showed 91% effectiveness in protecting infants. High coverage rates (>80%) were associated with substantial herd immunity effects, protecting unvaccinated populations.

Conclusions: Vaccination programs demonstrate remarkable effectiveness in reducing infectious disease burden across diverse settings. Success depends on achieving high coverage rates, addressing equity gaps, and maintaining public confidence. The evidence strongly supports continued investment in comprehensive immunization programs as a cornerstone of global health security.