Vaccine equity in low and middle income countries: a systematic review and meta-analysis

Abstract

Background Evidence to date has shown that inequality in health, and vaccination coverage in particular, can have ramifications to wider society. However, whilst individual studies have sought to characterise these heterogeneities in immunisation coverage at national level, few have taken a broad and quantitative view of the contributing factors to heterogeneity in immunisation coverage and impact, i.e. the number of cases, deaths, and disability-adjusted life years averted. This systematic review aims to highlight these geographic, demographic, and sociodemographic characteristics through a qualitative and quantitative approach, vital to prioritise and optimise vaccination policies. Methods A systematic review of two databases (PubMed and Web of Science) was undertaken using search terms and keywords to identify studies examining factors on immunisation inequality and heterogeneity in vaccination coverage. Inclusion criteria were applied independently by two researchers. Studies including data on key characteristics of interest were further analysed through a meta-analysis to produce a pooled estimate of the risk ratio using a random effects model for that characteristic. Results One hundred and eight studies were included in this review. We found that inequalities in wealth, education, and geographic access can affect vaccine impact and vaccination dropout. We estimated those living in rural areas were not significantly different in terms of full vaccination status compared to urban areas but noted considerable heterogeneity between countries. We found that females were 3% (95%CI[1%, 5%]) less likely to be fully vaccinated than males. Additionally, we estimated that children whose mothers had no formal education were 28% (95%CI[18%,47%]) less likely to be fully vaccinated than those whose mother had primary level, or above, education. Finally, we found that individuals in the poorest wealth quintile were 27% (95%CI [16%,37%]) less likely to be fully vaccinated than those in the richest. Conclusions We found a nuanced picture of inequality in vaccination coverage and access with wealth disparity dominating, and likely driving, other disparities. This review highlights the complex landscape of inequity and further need to design vaccination strategies targeting missed subgroups to improve and recover vaccination coverage following the COVID-19 pandemic. Trial registration Prospero, CRD42021261927

Advancing Immunization Coverage and Equity: A Structured Synthesis of Pro-Equity Strategies in 61 Gavi-Supported Countries

“…Zero-dose children are defined by the Immunisation Agenda 2030 consortium (IA2030) as those that lack access to or are never reached by routine immunization services, measured by the lack of the first dose of diphtheria-tetanus-pertussis containing vaccine (DTP1) [ 2 ]. Health inequities are significant drivers of the gaps in immunization coverage and challenges in reaching the most under-served communities in low- and middle-income countries (LMICs) [ 3 , 4 ]. It is estimated that half of zero-dose children reside in three key geographic contexts: urban poor areas, remote communities and conflict-affected settings [ 5 ].…”

“…It is estimated that half of zero-dose children reside in three key geographic contexts: urban poor areas, remote communities and conflict-affected settings [ 5 ]. Moreover, gender-related barriers to immunization create additional challenges, with indicators such as maternal education and age being significant determinants of immunization coverage [ 3 , 4 , 6 , 7 ].…”

Experiences and perceptions of COVID-19 infection and vaccination among Palestinian refugees in Jerash camp and Jordanian citizens: a comparative cross-sectional study by face-to-face interviews

“…Even before the COVID-19 pandemic, inequality in access to healthcare services was a major challenge in low- and middle-income countries [ 7 ]. Amid the pandemic, these countries experienced significant barriers related to lack of testing available, protective personal equipment, advanced healthcare services, as well as the global vaccine supply inequities [ 8 , 9 ]. Therefore, the pandemic exacerbating the challenges of health inequities in poor communities resulting in new waves of negative socio-economic consequences.…”

Madagascar's EPI vaccine programs: A systematic review uncovering the role of a child's sex and other barriers to vaccination

“…A majority of the global population of children with an incomplete vaccination series reside in LMICs (7). Several factors contribute to low rates of vaccine uptake in LMICs, including a lack of political support for vaccination campaigns, greater resource allocation to other health issues, and poor education and awareness about vaccines among healthcare workers and parents, specifically mothers (8)(9)(10). The lack of education about the benefits of immunization and risks of disease in LMICs further limits vaccine uptake, leading individuals to believe that immunization has a high cost-benefit ratio (8).…”