An Evaluation of the Early Impact of the COVID-19 Pandemic on Zambia’s Routine Immunization Program

Background Implications of the COVID-19 pandemic for both populations and healthcare systems are vast. In addition to morbidity and mortality from COVID-19, the pandemic also has disrupted local health systems, including reductions or delays in routine vaccination services and catch-up vaccination campaigns that could lead to outbreaks of other infectious diseases that result in an additional burden of disease and strain on the healthcare system.Methods and Findings We evaluated the impact of the COVID-19 pandemic on Zambia’s routine childhood immunization program in 2020 using multiple sources of data. We relied on district-level administrative vaccination coverage data and Zambia’s 2018 Demographic and Health Survey to project disruptions to routine childhood vaccination within the pandemic year 2020 (N=5,670). Next, we leveraged serological data to predict age-specific measles seroprevalence and assessed the impact of changes in vaccination coverage on measles outbreak risk in each district. We found minor disruptions to routine administration of measles-rubella and pentavalent vaccines in 2020. This was in part due to Zambia’s Child Health Week held in June of 2020 which helped to reach children missed during the first six months of the year. We estimated that the two-month delay in a measles-rubella vaccination campaign, originally planned for September of 2020 but conducted in November of 2020 as a result of the pandemic, had little impact on modeled district-specific measles outbreak risks.Conclusions The pandemic only minimally increased the number of children missed by measles-rubella and pentavalent vaccines in 2020. However, the ongoing SARS-CoV-2 transmission since our analysis concluded means efforts to maintain routine immunization services and minimize the risk of measles outbreaks will continue to be critical. Fortunately, the methodological framework developed in this analysis relied on routinely collected data and can be used to evaluate COVID-19 pandemic disruptions in Zambia following 2020 and in other countries or for other vaccines at a sub-national level.### Competing Interest StatementThe authors have declared no competing interest.### Funding StatementThe Bill and Melinda Gates Foundation (OPP1094816) funded this work.### Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:For the 2016 measles seroprevalence data, participants provided written informed consent, parental permission was obtained children under 18 years old, and assent was obtained for participants 10-17 years old. This serosurvey was conducted in accordance with relevant guidelines and regulations. Ethical approvals for protocols were provided by Johns Hopkins Bloomberg School of Public Health (00008423) as well as the Tropical Disease Research Center and the National Health Regulatory Agency in Zambia (TDRC/C4/01/2019).I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.YesData produced in the present study can be available upon reasonable request to the authors