Socioeconomic inequalities in vaccine uptake: A global umbrella review.

This global umbrella review aimed to synthesise evidence of socioeconomic inequalities in the uptake of routine vaccinations and identify the mechanisms that may contribute to the association. To our knowledge, no attempt has been made to synthesise the global body of systematic reviews across a variety of vaccines, geographical locations, and measures of SES. The inclusion criteria were as follows: studies assessing vaccination uptake according to education, income, occupation/employment, and/or area-level deprivation; any country or universally recommended routine vaccination (according to the WHO); qualitative or quantitative reviews, published 2011-present. The searches were performed in eight databases. The screening process followed PRISMA-E guidelines, each stage was performed by one reviewer, and a 10% sample checked by a second for consistency. Included reviews underwent data extraction, quality appraisal (AMSTAR-2), and narrative synthesis according to country-context. After deduplication, 9,163 reports underwent title and abstract screening, leaving 119 full texts to be assessed for eligibility. Overall, 26 studies were included in the umbrella review. Evidence for lower uptake amongst disadvantaged SES individuals was found in all 26 reviews. However, 17 reviews showed mixed results, as inverse associations were also identified (lower uptake for advantaged SES, and/or higher uptake for disadvantaged SES). Those that explored high-income countries had a greater prevalence of mixed findings than those focusing on low/middle-income countries. The two most frequently cited mechanisms were vaccination knowledge, and confidence in vaccination or vaccination providers. These mechanisms were often understood by review authors as varying by level of education. We find socioeconomic differences in routine vaccination uptake, but the association did not always follow a gradient. Whilst education may be associated with uptake globally, our study indicates that its role varies by country-context. A limitation is the overlap of some primary studies across the included systematic reviews.

Socioeconomic Inequalities and Vaccine Uptake: An Umbrella Review Protocol.

The effectiveness of immunization is widely accepted: it can successfully improve health outcomes by reducing the morbidity and mortality associated with vaccine-preventable diseases. In the era of pandemics, there is a pressing need to identify and understand the factors associated with vaccine uptake amongst different socioeconomic groups. The knowledge generated from research in this area can be used to inform effective interventions aimed at increasing uptake. This umbrella systematic review aims to determine whether there is an association between socioeconomic inequalities and rate of vaccine uptake globally. Specifically, the study aims to determine whether an individual's socioeconomic status, level of education, occupation, (un)-employment, or place of residence affects the uptake rate of routine vaccines. The following databases will be searched from 2011 to the present day: Medline (Ovid), Embase (Ovid), CINAHL (EBSCO), Cochrane CENTRAL, Science Citation Index (Web of Science), DARE, SCOPUS (Elsevier), and ASSIA (ProQuest). Systematic reviews will be either included or excluded based on a priori established eligibility criteria. The relevant data will then be extracted, quality appraised, and narratively synthesised. The synthesis will be guided by the theoretical framework developed for this review. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses Equity extension (PRISMA-E) guidance will be followed. This protocol has been registered on PROSPERO, ID: CRD42022334223.