Health impact of routine measles vaccination and supplementary immunisation activities in 14 high burden countries: a DynaMICE modelling study

Background WHO recommends ≥95% population coverage with two doses of measles-containing vaccine (MCV). Most countries used routine services to offer MCV1 and later, MCV2. Many countries conducted supplementary immunisation activities (SIAs), offering vaccination to all persons in a given age range irrespective of prior vaccination history. We estimated the relative impact of each dose and delivery route in 14 high burden countries. Methods We used an age-structured dynamic model (DynaMICE), to estimate the health impact of different vaccination strategies on measles susceptibility and burden over 2000-2020. We estimated their incremental impact using averted cases and deaths and their efficiency using number needed to vaccinate (NNV) to avert an additional measles case. Findings Compared to no vaccination, MCV1 implementation averted 823 million cases and 9.5 million deaths, with a median NNV of 1.41. Adding routine MCV2 to MCV1 further averted 108 million cases and 0.4 million deaths, while adding SIAs to MCV1 led to 249 million averted cases and 4 million deaths. Despite a larger incremental impact, adding SIAs to MCV1 showed reduced efficiency compared to adding routine MCV2, with median NNVs of 6.15 and 5.41, respectively. Interpretation Vaccination strategies including non-selective SIAs reach a greater proportion of unvaccinated children and reduce burden more than MCV2 alone, but efficiency is somewhat lower because of the wide age groups included in SIAs. This analysis provides insight to improve health impact and efficiency of measles vaccination. Funding Gavi, the Vaccine Alliance, and the Bill & Melinda Gates Foundation (OPP1157270) ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was funded by the Bill & Melinda Gates Foundation (OPP1157270) and Gavi, the Vaccine Alliance. This work was carried out as part of the Vaccine Impact Modelling Consortium (www.vaccineimpact.org), but the views expressed are those of the authors and not necessarily those of the Consortium or its funders. The funders were given the opportunity to review this paper prior to publication, but the final decision on the content of the publication was taken by the authors. This work was supported, in whole or in part, by the Bill & Melinda Gates Foundation, via the Vaccine Impact Modelling Consortium [Grant Number INV-009125]. Under the grant conditions of the Foundation, a Creative Commons Attribution 4.0 Generic License has already been assigned to the Author Accepted Manuscript version that might arise from this submission. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study used ONLY publicly available data that were originally located at: https://immunizationdata.who.int/pages/coverage/mcv.html (routine measles immunisation), https://www.who.int/entity/immunization/monitoring\_surveillance/data/Summary\_Measles_SIAs.xls (supplementary immunisation activities for measles), https://population.un.org/wpp/ (population statistics). 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. Yes I 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). Yes I 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. Yes Publicly available datasets were used for country models in this study, including measles vaccine coverage data from the World Health Organization (routine immunisation: https://immunizationdata.who.int/pages/coverage/mcv.html; supplementary immunisation activities: https://www.who.int/entity/immunization/monitoring\_surveillance/data/Summary\_Measles\_SIAs.xls) and population statistics from the United Nations World Prospect Project 2019 (https://population.un.org/wpp/). Computer codes for simulating measles burden and vaccination strategies based on the DynaMICE model are available in https://github.com/hfu915/dynamice\_ph.