Vaccination in Forcibly Displaced, Pediatric Populations: A Systematic Review and Meta-Analysis

Accessing forcibly displaced, pediatric populations for vaccination is challenging, and precise vaccination rates remain largely unknown.

To estimate vaccination coverage and identify factors associated with vaccination in forcibly displaced, pediatric populations.

Six databases were searched in November 2023-Ovid MEDLINE, Ovid EMBASE, PubMed, Scopus, Web of Science, and Cochrane-with no restrictions on language or publication dates. The search strategy included all appropriate controlled vocabulary and keywords for vaccination, pediatrics, and displaced populations.

Included studies were original research articles investigating vaccination in pediatric populations (<19 years) that were forcibly displaced as defined by the United Nations High Commissioner for Refugees. Reviews, nonresearch articles, and qualitative studies were excluded. Screening was conducted by 2 independent reviewers with discrepancies resolved by a third reviewer. Of 1731 studies identified, 294 underwent full-text review.

Data abstraction and quality assessment followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. A random-effects model was used to pool data. Data quality was assessed using the Downs and Black Checklist.

The primary outcome was pooled vaccination coverage, defined as the proportion vaccinated. Additionally, the factors associated with vaccination were pooled from reported unadjusted odds ratios (ORs) or adjusted ORs (aORs).

Of the 1731 studies identified, 39 studies from 24 countries were included. Based on 11 studies, the full vaccination coverage was 21% (95% CI, 11%-36%; I2 = 98.90%). Factors associated with greater odds of vaccination included having 2 or more children in the family (OR, 1.70; 95% CI, 1.43-2.02; I2 = 0.00%; aOR, 1.81; 95% CI, 1.28-2.57; I2 = 0.00%), higher levels of guardian education (OR, 1.60; 95% CI, 1.06-2.43; I2 = 71.60%), father's employment (OR, 2.75; 95% CI, 1.67-4.53; I2 = 0.00%), higher household income (OR = 1.33; 95% CI, 1.29-1.37; I2 = 0.00%), housing stability (OR, 2.80; 95% CI, 2.10-3.73; I2 = 0.00%; aOR, 2.62; 95% CI, 1.55-4.40; I2 = 0.00%), and residing in an area with more access to health care services (OR, 2.11; 95% CI, 1.44-3.09; I2 = 0.00%), while being forcibly displaced was associated with lower odds of vaccination (OR, 0.70; 95% CI, 0.55-0.89; I2 = 69.41%; aOR, 0.73; 95% CI, 0.63-0.86; I2 = 13.64%).

In this systematic review and meta-analysis of vaccination coverage among forcibly displaced, pediatric populations, vaccination coverage remained low. These findings highlight the urgent need for development of healthcare strategies and policies to close the immunization gap in this vulnerable population.