{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,22]],"date-time":"2026-07-22T22:09:03Z","timestamp":1784758143430,"version":"3.55.0"},"reference-count":24,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2023,3,7]],"date-time":"2023-03-07T00:00:00Z","timestamp":1678147200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"World Health Organization","award":["INV-016016"],"award-info":[{"award-number":["INV-016016"]}]},{"name":"JHPIEGO Zambia country office","award":["INV-016016"],"award-info":[{"award-number":["INV-016016"]}]},{"name":"Macha Research Trust","award":["INV-016016"],"award-info":[{"award-number":["INV-016016"]}]},{"name":"the Gavi the Vaccine Alliance through the Ministry of Health, Zambia","award":["INV-016016"],"award-info":[{"award-number":["INV-016016"]}]},{"name":"Grand Challenges Explorations initiative","award":["INV-016016"],"award-info":[{"award-number":["INV-016016"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Vaccines"],"abstract":"<jats:p>Background: Measles\u2013rubella supplementary immunization activities (MR-SIAs) are conducted to address inequalities in coverage and fill population immunity gaps when routine immunization services fail to reach all children with two doses of a measles-containing vaccine (MCV). We used data from a post-campaign coverage survey in Zambia to measure the proportion of measles zero-dose and under-immunized children who were reached by the 2020 MR-SIA and identified reasons associated with persistent inequalities following the MR-SIA. Methods: Children between 9 and 59 months were enrolled in a nationally representative, cross-sectional, multistage stratified cluster survey in October 2021 to estimate vaccination coverage during the November 2020 MR-SIA. Vaccination status was determined by immunization card or through caregivers\u2019 recall. MR-SIA coverage and the proportion of measles zero-dose and under-immunized children reached by MR-SIA were estimated. Log-binomial models were used to assess risk factors for missing the MR-SIA dose. Results: Overall, 4640 children were enrolled in the nationwide coverage survey. Only 68.6% (95% CI: 66.7%, 70.6%) received MCV during the MR-SIA. The MR-SIA provided MCV1 to 4.2% (95% CI: 0.9%, 4.6%) and MCV2 to 6.3% (95% CI: 5.6%, 7.1%) of enrolled children, but 58.1% (95% CI: 59.8%, 62.8%) of children receiving the MR-SIA dose had received at least two prior MCV doses. Furthermore, 27.8% of measles zero-dose children were vaccinated through the MR-SIA. The MR-SIA reduced the proportion of measles zero-dose children from 15.1% (95% CI: 13.6%, 16.7%) to 10.9% (95% CI: 9.7%, 12.3%). Zero-dose and under-immunized children were more likely to miss MR-SIA doses (prevalence ratio (PR): 2.81; 95% CI: 1.80, 4.41 and 2.22; 95% CI: 1.21 and 4.07) compared to fully vaccinated children. Conclusions: The MR-SIA reached more under-immunized children with MCV2 than measles zero-dose children with MCV1. However, improvement is needed to reach the remaining measles zero-dose children after SIA. One possible solution to address the inequalities in vaccination is to transition from nationwide non-selective SIAs to more targeted and selective strategies.<\/jats:p>","DOI":"10.3390\/vaccines11030608","type":"journal-article","created":{"date-parts":[[2023,3,8]],"date-time":"2023-03-08T03:29:05Z","timestamp":1678246145000},"page":"608","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Challenges Addressing Inequalities in Measles Vaccine Coverage in Zambia through a Measles\u2013Rubella Supplementary Immunization Activity during the COVID-19 Pandemic"],"prefix":"10.3390","volume":"11","author":[{"given":"Yangyupei","family":"Yang","sequence":"first","affiliation":[{"name":"Department of International Health, International Vaccine Access Center, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21231, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6184-531X","authenticated-orcid":false,"given":"Natalya","family":"Kostandova","sequence":"additional","affiliation":[{"name":"Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21231, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Francis Dien","family":"Mwansa","sequence":"additional","affiliation":[{"name":"Ministry of Health, Government of the Republic of Zambia, Lusaka 10101, Zambia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chola","family":"Nakazwe","sequence":"additional","affiliation":[{"name":"Zambia Statistics Agency, Lusaka 10101, Zambia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Harriet","family":"Namukoko","sequence":"additional","affiliation":[{"name":"Zambia Statistics Agency, Lusaka 10101, Zambia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Constance","family":"Sakala","sequence":"additional","affiliation":[{"name":"Ministry of Health, Government of the Republic of Zambia, Lusaka 10101, Zambia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Patricia","family":"Bobo","sequence":"additional","affiliation":[{"name":"Ministry of Health, Government of the Republic of Zambia, Lusaka 10101, Zambia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Penelope Kalesha","family":"Masumbu","sequence":"additional","affiliation":[{"name":"Zambia Country Office, World Health Organization, Lusaka 10101, Zambia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bertha","family":"Nachinga","sequence":"additional","affiliation":[{"name":"Zambia Statistics Agency, Lusaka 10101, Zambia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David","family":"Ngula","sequence":"additional","affiliation":[{"name":"Ministry of Health, Government of the Republic of Zambia, Lusaka 10101, Zambia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6271-6387","authenticated-orcid":false,"given":"Andrea C.","family":"Carcelen","sequence":"additional","affiliation":[{"name":"Department of International Health, International Vaccine Access Center, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21231, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christine","family":"Prosperi","sequence":"additional","affiliation":[{"name":"Department of International Health, International Vaccine Access Center, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21231, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Amy K.","family":"Winter","sequence":"additional","affiliation":[{"name":"Department of Epidemiology, University of Georgia, Athens, GA 30602, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"William J.","family":"Moss","sequence":"additional","affiliation":[{"name":"Department of International Health, International Vaccine Access Center, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21231, USA"},{"name":"Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21231, USA"},{"name":"W Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21231, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5389-5966","authenticated-orcid":false,"given":"Simon","family":"Mutembo","sequence":"additional","affiliation":[{"name":"Department of International Health, International Vaccine Access Center, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21231, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,3,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1489","DOI":"10.15585\/mmwr.mm7147a1","article-title":"Progress Toward Regional Measles Elimination\u2014Worldwide, 2000\u20132021","volume":"71","author":"Minta","year":"2022","journal-title":"Morb. Mortal. Wkly. Rep."},{"key":"ref_2","unstructured":"World Health Organization (2020). Rubella vaccines: WHO position paper\u2014July 2020. Wkly. Epidemiol. Rec., 27, 306\u2013324."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"e280","DOI":"10.1016\/S2214-109X(20)30481-2","article-title":"A scorecard of progress towards measles elimination in 15 west African countries, 2001\u20132019: A retrospective, multicountry analysis of national immunisation coverage and surveillance data","volume":"9","author":"Wariri","year":"2021","journal-title":"Lancet Glob. Health"},{"key":"ref_4","unstructured":"World Health Organization (2023, January 05). Immunization Zambia 2022 Country Profile. Available online: https:\/\/www.who.int\/publications\/m\/item\/immunization-zmb-2022-country-profile."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"e186","DOI":"10.1016\/S2214-109X(21)00512-X","article-title":"Impact of the SARS-CoV-2 pandemic on routine immunisation services: Evidence of disruption and recovery from 170 countries and territories","volume":"10","author":"Shet","year":"2022","journal-title":"Lancet Glob. Health"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1016\/j.ijid.2022.04.005","article-title":"Impact of the SARS-CoV-2 pandemic on vaccine-preventable disease campaigns","volume":"119","author":"Ho","year":"2022","journal-title":"Int. J. Infect. Dis."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"360","DOI":"10.1038\/s41591-021-01237-5","article-title":"A dangerous measles future looms beyond the COVID-19 pandemic","volume":"27","author":"Durrheim","year":"2021","journal-title":"Nat. Med."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"522","DOI":"10.1016\/S0140-6736(21)01337-4","article-title":"Estimating global and regional disruptions to routine childhood vaccine coverage during the COVID-19 pandemic in 2020: A modelling study","volume":"398","author":"Causey","year":"2021","journal-title":"Lancet"},{"key":"ref_9","unstructured":"Ministry of Health Zambia (2021). Post Coverage Measles-Rubella Campaign Evaluation Survey, Ministry of Health Zambia."},{"key":"ref_10","unstructured":"World Health Organization (2018). World Health Organization Vaccination Coverage Cluster Surveys: Reference Manual, World Health Organization."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"468","DOI":"10.1017\/S0950268817003077","article-title":"Correlation between measles vaccine doses: Implications for the maintenance of elimination","volume":"146","author":"McKee","year":"2018","journal-title":"Epidemiol. Infect."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"979","DOI":"10.1016\/j.vaccine.2019.11.020","article-title":"Using models to shape measles control and elimination strategies in low- and middle-income countries: A review of recent applications","volume":"38","author":"Cutts","year":"2020","journal-title":"Vaccine"},{"key":"ref_13","unstructured":"Gavi (2023, January 05). Gavi Phase 5 Strategy (2021\u20132025). Available online: https:\/\/www.gavi.org\/our-alliance\/strategy\/phase-5-2021-2025."},{"key":"ref_14","unstructured":"R Core Team (2019). R: A Language and Environment for Statistical Computing, R Foundation for Statistical Computing. Available online: https:\/\/www.R-project.org\/."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1","DOI":"10.18637\/jss.v009.i08","article-title":"Analysis of Complex Survey Samples","volume":"9","author":"Lumley","year":"2004","journal-title":"J. Stat. Softw."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Wickham, H. (2016). Ggplot2: Elegant Graphics for Data Analysis, Springer.","DOI":"10.1007\/978-3-319-24277-4"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2387","DOI":"10.1016\/j.vaccine.2019.02.037","article-title":"Measles and rubella serosurvey identifies rubella immunity gap in young adults of childbearing age in Zambia: The added value of nesting a serological survey within a post-campaign coverage evaluation survey","volume":"37","author":"Hayford","year":"2019","journal-title":"Vaccine"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"e00516","DOI":"10.1002\/hsr2.516","article-title":"Impact ofCOVID-19 pandemic on routine vaccination coverage of children and adolescents: A systematic review","volume":"5","author":"SeyedAlinaghi","year":"2022","journal-title":"Health Sci. Rep."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"170","DOI":"10.1016\/j.vaccine.2017.10.080","article-title":"Impact of measles supplementary immunization activities on reaching children missed by routine programs","volume":"36","author":"Portnoy","year":"2017","journal-title":"Vaccine"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"6093","DOI":"10.1016\/j.vaccine.2019.08.049","article-title":"The cost saving opportunity of introducing a card review into measles-containing vaccination campaigns","volume":"37","author":"Hagedorn","year":"2019","journal-title":"Vaccine"},{"key":"ref_21","first-page":"194","article-title":"Reasons for incomplete vaccination and factors for missed opportunities among rural Nigerian children","volume":"3","author":"Abdulraheem","year":"2011","journal-title":"J. Public Health Epidemiol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"e007479","DOI":"10.1136\/bmjgh-2021-007479","article-title":"Using geospatial models to map zero-dose children: Factors associated with zero-dose vaccination status before and after a mass measles and rubella vaccination campaign in Southern province, Zambia","volume":"6","author":"Arambepola","year":"2021","journal-title":"BMJ Glob. Health"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"82","DOI":"10.1186\/s12939-022-01678-5","article-title":"Vaccine equity in low and middle income countries: A systematic review and meta-analysis","volume":"21","author":"Ali","year":"2022","journal-title":"Int. J. Equity Health"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"358","DOI":"10.3329\/jhpn.v27i3.3378","article-title":"Factors Associated with Missed Vaccination during Mass Immunization Campaigns","volume":"27","author":"Weiss","year":"2009","journal-title":"J. Health Popul. Nutr."}],"container-title":["Vaccines"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-393X\/11\/3\/608\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T18:49:52Z","timestamp":1760122192000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-393X\/11\/3\/608"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,3,7]]},"references-count":24,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2023,3]]}},"alternative-id":["vaccines11030608"],"URL":"https:\/\/doi.org\/10.3390\/vaccines11030608","relation":{},"ISSN":["2076-393X"],"issn-type":[{"value":"2076-393X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,3,7]]}}}