Background: Invasive pneumococcal disease (IPD) and pneumonia are major causes of morbidity, especially in developing countries. While pneumococcal disease rates differences between various populations are well known, data are scarce regarding disparities in PCV impact on pneumococcal disease rates between populations living in the same country.

Objective: The aim of this systematic literature review was to describe disparities in PCV impact between different populations.

Methods: A systematic literature search was performed using the PubMed database. Studies evaluating pneumococcal disease rates at any age were included. The search was limited to articles written in English and published between 2000 and 2015. Independent extraction of articles was performed by two authors (NS, SB-S). Search terms included: pneumococcus, pneumococcal disease, IPD, pneumonia, PCV, pneumococcal vaccine, population, race, ethnicity, differences, and disparity. We defined resource-poor populations as African-Americans, Aboriginal, Alaska natives and Navajo native-Americans populations compared with the respective resource-rich populations, including White, non-Aboriginal, non-Alaska natives and general US population.

Results: Eighteen articles meeting the selection criteria were identified; 17 regarding IPD and one regarding pneumonia. Nine articles compared IPD rates in African-Americans and Whites in the US, six compared Aboriginal and non-Aboriginal populations; two compared Alaska natives vs. non-native Alaskans in the US and one article compared Navajo native-Americans and general population in the US. Only minor difference where usually noted in the incidence rate ratios (IRRs) comparing pre- and post-PCV rates of IPD and pneumonia between resource rich and resource poor populations. In contrast, absolute rate reductions were higher in resource-poor compared with resource-rich populations.

Conclusion: While differences in IPD and pneumonia rates between resource-poor and resource-rich populations were decreased following PCV introduction, disparity is still apparent and is not fully eliminated in any of the studies. Younger (<2years) populations in resource-poor populations seem to benefit the most from PCV introduction.