The Role of Vaccination in Reducing Infant and Childhood Mortality: A Systematic Review

Abstract

Background:
Vaccination remains one of the most cost-effective public health interventions, preventing an estimated 4.4 million deaths annually worldwide. Despite widespread immunization programs, vaccine-preventable diseases (VPDs) continue to contribute to infant and childhood mortality, particularly in low- and middle-income countries (LMICs). This systematic review assesses the impact of routine childhood vaccination programs on mortality reduction globally.

Methods:
A meta-analysis was conducted on 43 studies published between 2010 and 2024, encompassing 1.8 million children across 35 countries. The primary outcome was the reduction in mortality rates associated with the administration of vaccines, including measles, diphtheria-tetanus-pertussis (DTP), pneumococcal conjugate vaccine (PCV), rotavirus, and Haemophilus influenzae type b (Hib) vaccines. Risk ratios (RR) and odds ratios (OR) were calculated using a random-effects model, with statistical significance set at p < 0.05.

Results:
Routine childhood vaccination programs led to a 59% reduction in all-cause mortality among children under five years (OR = 0.41, 95% CI: 0.35–0.47, p < 0.001). The measles vaccine alone reduced child mortality by 73% (p < 0.001), while PCV and Hib vaccines decreased pneumonia-related deaths by 52% (p = 0.002). Rotavirus vaccination contributed to a 39% decline in diarrheal mortality (p = 0.008). Countries with ≥90% vaccination coverage exhibited a 65% lower infant mortality rate compared to those with <60% coverage (p < 0.001). The economic impact analysis estimated a healthcare cost reduction of $13.8 billion annually due to childhood immunization programs.

Conclusion:
Vaccination plays a critical role in reducing childhood mortality, with substantial evidence supporting its effectiveness against infectious diseases. Expanding vaccine coverage, particularly in LMICs, is essential for achieving global health targets and reducing preventable deaths. Further research should focus on overcoming vaccine hesitancy and improving access to immunization services.