The challenge of protracted measles outbreaks in Kismayo, Somalia: A mixed-method investigation of measles burden and vaccination coverage during a 2020–2021 outbreak

There was a protracted measles outbreak in Kismayo, Somalia between 2020-2021. The outbreak persisted despite availability of measles containing vaccine (MCV) through Expanded Program on Immunization (EPI) services and reactive vaccination campaigns. We sought to estimate measles burden and MCV coverage during the outbreak while further identifying barriers and facilitators to care and vaccinations. We adopted a cross-sectional, sequential mixed-method approach with a retrospective household survey followed by key informant interviews (KIIs) and focus group discussions (FGDs). We used proxy-reported interview data from a household survey with a two-year recall period to estimate attack rates (ARs), case fatality ratios (CFRs), measles-specific mortality and MCV coverage. We performed thematic analysis on qualitative data from 12 KIIs and 8 FGDs. We surveyed 1,050 households representing 6,664 individuals and estimated an urban population of 405,181 (95%CI: 389,335-422,331). We identified 338 measles cases (AR: 5.1% [95%CI: 4.6-5.6]) and 11 measles deaths (CFR: 3.3% [95%CI: 1.4-5.2]). During the outbreak, we interpolated that 20,664 (95%CI: 17,909-21,651) measles cases and 682 (95%CI: 251-1230) deaths occurred across Kismayo. At start of recall, 49.5% (95%CI: 46.5-52.6) aged 6-59 months had one-or-more doses of MCV and this increased to 69.6% (95%CI: 66.9-72.2) by end of recall. Thematic analysis produced qualitative insights on barriers to accessing medical care, barriers to routine vaccination through EPI, barriers to vaccination through mass campaigns and facilitating factors for care and vaccination. We show an unacceptably high burden of measles due to limited access to medical care and low MCV coverage despite a widespread willingness to be vaccinated. To mitigate the problem of protracted outbreaks, we suggest adopting a consistent, community-centered approach to risk communication and community engagement, reducing non-healthcare costs associated with accessing care, ensuring daily availability of EPI vaccinations in all public facilities and overhauling the ways in which mass vaccination campaigns are implemented.