{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,4]],"date-time":"2026-10-04T03:26:32Z","timestamp":1791084392463,"version":"4.1.0"},"reference-count":62,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2021,1,22]],"date-time":"2021-01-22T00:00:00Z","timestamp":1611273600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJERPH"],"abstract":"<jats:p>The COVID-19 pandemic has had an impact on health service delivery, including immunization programs, and this review assesses the impact on vaccine coverage across the globe and identifies the potential underlying factors. A systematic search strategy was employed on PubMed, Embase, MedRxiv, BioRxiv, and WHO COVID-19 databases from December 2019 till 15 September 2020. Two review authors independently assessed studies for inclusion, assessed quality, and extracted the data (PROSPERO registration #CRD42020182363). A total of 17 observational studies were included. The findings suggest that there was a reduction in the vaccination coverage and decline in total number of vaccines administered, which led to children missing out on their vaccine doses. An approximately fourfold increase was also observed in polio cases in polio endemic countries. Factors contributing to low vaccine coverage included fear of being exposed to the virus at health care facilities, restriction on city-wide movements, shortage of workers, and diversion of resources from child health to address the pandemic. As the world re-strategizes for the post-2020 era, we should not let a crisis go to waste as they provide an opportunity to establish guidelines and allocate resources for future instances. High-quality supplementary immunization activities and catch-up programs need to be established to address gaps during the pandemic era.<\/jats:p>","DOI":"10.3390\/ijerph18030988","type":"journal-article","created":{"date-parts":[[2021,1,25]],"date-time":"2021-01-25T02:07:00Z","timestamp":1611540420000},"page":"988","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":213,"title":["The Impact of the COVID-19 Pandemic on Immunization Campaigns and Programs: A Systematic Review"],"prefix":"10.3390","volume":"18","author":[{"given":"Zohra S.","family":"Lassi","sequence":"first","affiliation":[{"name":"Robinson Research Institute, The University of Adelaide, Adelaide, SA 5005, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3641-3897","authenticated-orcid":false,"given":"Rabia","family":"Naseem","sequence":"additional","affiliation":[{"name":"Division of Women and Child Health, The Aga Khan University, Karachi 74500, Pakistan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rehana A.","family":"Salam","sequence":"additional","affiliation":[{"name":"Division of Women and Child Health, The Aga Khan University, Karachi 74500, Pakistan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Faareha","family":"Siddiqui","sequence":"additional","affiliation":[{"name":"Division of Women and Child Health, The Aga Khan University, Karachi 74500, Pakistan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jai K.","family":"Das","sequence":"additional","affiliation":[{"name":"Division of Women and Child Health, The Aga Khan University, Karachi 74500, Pakistan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,1,22]]},"reference":[{"key":"ref_1","unstructured":"(2020, July 31). WHO Director-General\u2019s Opening Remarks at the Media Briefing on COVID-19\u201411 March 2020. Available online: https:\/\/www.who.int\/dg\/speeches\/detail\/who-director-general-s-opening-remarks-at-the-media-briefing-on-covid-19---11-march-2020."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"704","DOI":"10.1097\/TA.0b013e31825472d7","article-title":"Trauma caused by falling objects at construction sites","volume":"73","author":"Atique","year":"2012","journal-title":"J. Trauma Acute Care Surg."},{"key":"ref_3","first-page":"Cd008145","article-title":"Interventions for improving coverage of childhood immunisation in low- and middle-income countries","volume":"7","author":"Wiysonge","year":"2016","journal-title":"Cochrane Database Syst. Rev."},{"key":"ref_4","unstructured":"PAHO (2020). The Immunization Program in the Context of the COVID-19 Pandemic, 26 March 2020, PAHO."},{"key":"ref_5","unstructured":"WHO (2020, July 31). Guiding Principles for Immunization Activities during the COVID-19 Pandemic. Interim Guidance. 26 March 2020. Available online: https:\/\/apps.who.int\/iris\/bitstream\/handle\/10665\/331590\/WHO-2019-nCoV-immunization_services-2020.1-eng.pdf."},{"key":"ref_6","unstructured":"WHO (2019). Progress and Challenges with Achieving Universal Immunization Coverage. 2017 WHO\/UNICEF Estimates of National Immunization Coverage [internet], World Health Organization."},{"key":"ref_7","unstructured":"WHO (2020, August 05). At Least 80 Million Children under One at Risk of Diseases Such as Diphtheria, Measles and Polio as COVID-19 Disrupts Routine Vaccination Efforts, Warn GAVI, WHO and UNICEF. Available online: https:\/\/www.who.int\/news-room\/detail\/22-05-2020-at-least-80-million-children-under-one-at-risk-of-diseases-such-as-diphtheria-measles-and-polio-as-covid-19-disrupts-routine-vaccination-efforts-warn-gavi-who-and-unicef."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"546","DOI":"10.1016\/S1473-3099(20)30304-2","article-title":"COVID-19 disrupts vaccine delivery","volume":"20","author":"Nelson","year":"2020","journal-title":"Lancet Infect. Dis."},{"key":"ref_9","first-page":"70","article-title":"Challenges of COVID-19 in children in low- and middle-income countries","volume":"35","author":"Zar","year":"2020","journal-title":"Paediatr. Respir. Rev."},{"key":"ref_10","unstructured":"GAVI (2020, August 09). COVID-19: Massive Impact on Lower-Income Countries Threatens More Disease Outbreaks. Available online: https:\/\/www.gavi.org\/news\/media-room\/covid-19-massive-impact-lower-income-countries-threatens-more-disease-outbreaks."},{"key":"ref_11","unstructured":"Hoffman, J.M.R. (2020, August 05). Slowing the Coronavirus is Speeding the Spread of Other Diseases. New York Times. Available online: https:\/\/www.nytimes.com\/2020\/06\/14\/health\/coronavirus-vaccines-measles.html."},{"key":"ref_12","unstructured":"(2020, August 05). This Week. Polio This Week as of 13 January 2020. Available online: http:\/\/polioeradication.org\/polio-today\/polio-now\/this-week\/."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"e65","DOI":"10.1016\/S2666-5247(20)30040-9","article-title":"COVID-19 and measles: Double trouble for Burundi","volume":"1","author":"Bagcchi","year":"2020","journal-title":"Lancet Microbe"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"446","DOI":"10.1038\/d41586-020-01011-6","article-title":"Why measles deaths are surging- and coronavirus could make it worse","volume":"580","author":"Roberts","year":"2020","journal-title":"Nature"},{"key":"ref_15","unstructured":"Initiative, M.a.R. (2020, July 31). More than 117 Million Children at Risk of Missing Out on Measles Vaccine, as COVID-19 Surges, Available online: https:\/\/measlesrubellainitiative.org\/measles-news\/more-than-117-million-children-at-risk-of-missing-out-on-measles-vaccines-as-covid-19-surges\/."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"101656","DOI":"10.1016\/j.tmaid.2020.101656","article-title":"COVID-19 and dengue, co-epidemics in Ecuador and other countries in Latin America: Pushing strained health care systems over the edge","volume":"37","author":"Navarro","year":"2020","journal-title":"Travel Med. Infect. Dis."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Nacher, M., Douine, M., Gaillet, M., Flamand, C., Rousset, D., Rousseau, C., Mahdaoui, C., Carroll, S., Valdes, A., and Passard, N. (2020). Simultaneous dengue and COVID-19 epidemics: Difficult days ahead?. PLoS Negl. Trop. Dis., 14.","DOI":"10.1371\/journal.pntd.0008426"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"m2879","DOI":"10.1136\/bmj.m2879","article-title":"Lessons from Ebola as DRC grapples with conflict, measles, and covid-19","volume":"370","author":"Adepoju","year":"2020","journal-title":"BMJ"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Sun, X., Samba, T.T., Yao, J., Yin, W., Xiao, L., Liu, F., Liu, X., Zhou, J., Kou, Z., and Fan, H. (2017). Impact of the Ebola outbreak on routine immunization in western area, Sierra Leone\u2014A field survey from an Ebola epidemic area. BMC Public Health, 17.","DOI":"10.1186\/s12889-017-4242-7"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"669","DOI":"10.1016\/S1473-3099(20)30243-7","article-title":"Estimates of the severity of coronavirus disease 2019: A model-based analysis","volume":"20","author":"Verity","year":"2020","journal-title":"Lancet Infect Dis"},{"key":"ref_21","unstructured":"WHO (2020). The Potential Impact of Health Service Disruptions on the Burden of Malaria: A Modelling Analysis for Countries in Sub-Saharan Africa, World Health Organization."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"539","DOI":"10.3201\/eid0404.980404","article-title":"Diphtheria in the former Soviet Union: Reemergence of a pandemic disease","volume":"4","author":"Vitek","year":"1998","journal-title":"Emerg. Infect. Dis."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Moher, D., Liberati, A., Tetzlaff, J., and Altman, D.G. (2009). Preferred reporting items for systematic reviews and meta-analyses: The PRISMA statement. PLoS Med., 6.","DOI":"10.1371\/journal.pmed.1000097"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"263","DOI":"10.1080\/10903127.2018.1489019","article-title":"Correlation between the revised trauma score and injury severity score: Implications for prehospital trauma triage","volume":"23","author":"Galvagno","year":"2019","journal-title":"Prehospital Emerg. Care"},{"key":"ref_25","first-page":"31","article-title":"Mass immunization programs: Principles and standards","volume":"304","author":"Grabenstein","year":"2006","journal-title":"Curr. Top Microbiol. Immunol."},{"key":"ref_26","unstructured":"Covidence (2017). Covidence Systematic Review Software, Covidence."},{"key":"ref_27","unstructured":"NHLBI (2019). Study Quality Assessment Tools, NHLBI."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"141","DOI":"10.1002\/jmv.26240","article-title":"COVID-19 in Pakistan: Impact on global polio eradication initiative","volume":"93","author":"Haqqi","year":"2021","journal-title":"J. Med. Virol."},{"key":"ref_29","first-page":"E125","article-title":"Paediatric activities and adherence to vaccinations during the COVID-19 epidemic period in Tuscany, Italy: A survey of paediatricians","volume":"61","author":"Bechini","year":"2020","journal-title":"J. Prev. Med. Hyg."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"630","DOI":"10.15585\/mmwr.mm6920e1","article-title":"Decline in Child Vaccination Coverage During the COVID-19 Pandemic\u2014Michigan Care Improvement Registry, May 2016\u2013May 2020","volume":"69","author":"Bramer","year":"2020","journal-title":"MMWR Morb. Mortal. Wkly. Rep."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"517","DOI":"10.3389\/fped.2020.00517","article-title":"Child Healthcare and Immunizations in Sub-Saharan Africa During the COVID-19 Pandemic","volume":"8","author":"Buonsenso","year":"2020","journal-title":"Front. Pediatr."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"E921","DOI":"10.1503\/cmaj.201008","article-title":"Addressing the indirect effects of COVID-19 on the health of children and young people","volume":"192","author":"Chanchlani","year":"2020","journal-title":"CMAJ"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"e1118","DOI":"10.1016\/S2214-109X(20)30290-4","article-title":"Impact of COVID-19 lockdown on routine immunisation in Karachi, Pakistan","volume":"8","author":"Chandir","year":"2020","journal-title":"Lancet Glob. Health"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"784","DOI":"10.15585\/mmwr.mm6925a4","article-title":"Progress Toward Polio Eradication-Worldwide, January 2018\u2013March 2020","volume":"69","author":"Chard","year":"2020","journal-title":"MMWR Morb. Mortal. Wkly. Rep."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Kirmani, S., and Saleem, A. (2020). Impact of COVID-19 pandemic on paediatric services at a referral centre in Pakistan: Lessons from a low-income and middle-income country setting. Arch. Dis. Child.","DOI":"10.1136\/archdischild-2020-319424"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"999","DOI":"10.15585\/mmwr.mm6930a3","article-title":"Notes from the Field: Rebound in Routine Childhood Vaccine Administration Following Decline During the COVID-19 Pandemic\u2014New York City, March 1\u2013June 27, 2020","volume":"69","author":"Papadouka","year":"2020","journal-title":"MMWR Morb. Mortal. Wkly. Rep."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"McDonald, H.I., Tessier, E., White, J.M., Woodruff, M., Knowles, C., Bates, C., Parry, J., Walker, J.L., Scott, J.A., and Smeeth, L. (2020). Early impact of the coronavirus disease (COVID-19) pandemic and physical distancing measures on routine childhood vaccinations in England, January to April 2020. Euro Surveill., 25.","DOI":"10.2807\/1560-7917.ES.2020.25.19.2000848"},{"key":"ref_38","first-page":"129","article-title":"Recovering lost vaccine coverage due to COVID-19 pandemic","volume":"21","year":"2020","journal-title":"Vacunas"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"591","DOI":"10.15585\/mmwr.mm6919e2","article-title":"Effects of the COVID-19 Pandemic on Routine Pediatric Vaccine Ordering and Administration\u2014United States, 2020","volume":"69","author":"Santoli","year":"2020","journal-title":"MMWR Morb. Mortal. Wkly. Rep."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"m2392","DOI":"10.1136\/bmj.m2392","article-title":"Routine vaccination during covid-19 pandemic response","volume":"369","author":"Saxena","year":"2020","journal-title":"BMJ"},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Siedner, M.J., Kraemer, J.D., Meyer, M.J., Harling, G., Mngomezulu, T., Gabela, P., Dlamini, S., Gareta, D., Majozi, N., and Ngwenya, N. (2020). Access to primary healthcare during lockdown measures for COVID-19 in rural South Africa: A longitudinal cohort study. medRxiv.","DOI":"10.1101\/2020.05.15.20103226"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"859","DOI":"10.15585\/mmwr.mm6927a2","article-title":"Provision of Pediatric Immunization Services During the COVID-19 Pandemic: An Assessment of Capacity Among Pediatric Immunization Providers Participating in the Vaccines for Children Program\u2014United States, May 2020","volume":"69","author":"Vogt","year":"2020","journal-title":"MMWR Morb. Mortal. Wkly. Rep."},{"key":"ref_43","unstructured":"GAVI (2020). COVID-19: Situation Report #14. COVID-19 Situation Reports, GAVI."},{"key":"ref_44","unstructured":"Weill, A., Drouin, J., Desplas, D., Cuenot, F., Dray Spira, R., and Zureik, M. (2020). Usage des M\u00e9dicaments de Ville en France Durant L\u2019\u00e9pid\u00e9mie de la Covid-19\u2013Point de Situation Apr\u00e8s les 8 Semaines de Confinement et une Semaine de Post-Confinement (jusqu\u2019au 17 mai 2020). \u00c9tude Pharmaco-\u00c9pid\u00e9miologique \u00e0 Partir des Donn\u00e9es de Remboursement du SNDS, GIS ANSM\u2013Cnam."},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"The Lancet Child (2020). Pandemic school closures: Risks and opportunities. Lancet Child. Adolesc. Health, 4, 341.","DOI":"10.1016\/S2352-4642(20)30105-X"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"497","DOI":"10.1016\/S0140-6736(20)30183-5","article-title":"Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China","volume":"395","author":"Huang","year":"2020","journal-title":"Lancet"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"371","DOI":"10.1016\/j.jmii.2020.02.011","article-title":"Are children less susceptible to COVID-19?","volume":"53","author":"Lee","year":"2020","journal-title":"J. Microbiol. Immunol. Infect."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"e901","DOI":"10.1016\/S2214-109X(20)30229-1","article-title":"Early estimates of the indirect effects of the COVID-19 pandemic on maternal and child mortality in low-income and middle-income countries: A modelling study","volume":"8","author":"Roberton","year":"2020","journal-title":"Lancet Glob. Health"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"e001715","DOI":"10.1136\/bmjgh-2019-001715","article-title":"Risk factors for death among children aged 5-14 years hospitalised with pneumonia: A retrospective cohort study in Kenya","volume":"4","author":"Macpherson","year":"2019","journal-title":"BMJ Glob. Health"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"605","DOI":"10.1016\/S0140-6736(19)32540-1","article-title":"A future for the world\u2019s children? A WHO-UNICEF-Lancet Commission","volume":"395","author":"Clark","year":"2020","journal-title":"Lancet"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"845","DOI":"10.1001\/jama.2020.13092","article-title":"COVID-19 and School Closures","volume":"324","author":"Donohue","year":"2020","journal-title":"JAMA"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"e243","DOI":"10.1016\/S2468-2667(20)30084-0","article-title":"COVID-19, school closures, and child poverty: A social crisis in the making","volume":"5","author":"Parolin","year":"2020","journal-title":"Lancet Public Health"},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"552","DOI":"10.1056\/NEJMra1110897","article-title":"Health Care Systems in Low- and Middle-Income Countries","volume":"370","author":"Mills","year":"2014","journal-title":"N. Engl. J. Med."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"e1267","DOI":"10.1016\/S2214-109X(20)30308-9","article-title":"Routine childhood immunisation during the COVID-19 pandemic in Africa: A benefit-risk analysis of health benefits versus excess risk of SARS-CoV-2 infection","volume":"8","author":"Abbas","year":"2020","journal-title":"Lancet Glob. Health"},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"1207","DOI":"10.1001\/jamapsychiatry.2020.2174","article-title":"The Differential Outcomes of Coronavirus Disease 2019 in Low- and Middle-Income Countries vs High-Income Countries","volume":"77","author":"Vigo","year":"2020","journal-title":"JAMA Psychiatry"},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"1235","DOI":"10.1016\/S1473-3099(19)30395-0","article-title":"Immunogenicity, effectiveness, and safety of measles vaccination in infants younger than 9 months: A systematic review and meta-analysis","volume":"19","author":"Strebel","year":"2019","journal-title":"Lancet Infect. Dis."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"e617","DOI":"10.1016\/S2214-109X(16)30141-3","article-title":"State of inequality in diphtheria-tetanus-pertussis immunisation coverage in low-income and middle-income countries: A multicountry study of household health surveys","volume":"4","author":"Hosseinpoor","year":"2016","journal-title":"Lancet Glob. Health"},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"794","DOI":"10.2471\/BLT.15.162172","article-title":"Inequalities in full immunization coverage: Trends in low- and middle-income countries","volume":"94","author":"Barros","year":"2016","journal-title":"Bull. World Health Organ."},{"key":"ref_59","unstructured":"(2020, September 06). G.P.E.I. Endemic Countries. Available online: http:\/\/polioeradication.org\/where-we-work\/polio-endemic-countries\/."},{"key":"ref_60","unstructured":"(2020, September 06). Niger Reports New Polio Outbreak. Available online: https:\/\/www.afro.who.int\/news\/niger-reports-new-polio-outbreak."},{"key":"ref_61","doi-asserted-by":"crossref","unstructured":"Singh, V.K., Mishra, A., Singh, S., Kumar, P., Singh, M., Jagannath, C., and Khan, A. (2020). Emerging prevention and treatment strategies to control COVID-19. Pathogens, 9.","DOI":"10.3390\/pathogens9060501"},{"key":"ref_62","doi-asserted-by":"crossref","unstructured":"S\u0142omka, A., Kowalewski, M., and \u017bekanowska, E. (2020). Coronavirus Disease 2019 (COVID\u201319): A Short Review on Hematological Manifestations. Pathogens, 9.","DOI":"10.3390\/pathogens9060493"}],"container-title":["International Journal of Environmental Research and Public Health"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1660-4601\/18\/3\/988\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T05:14:19Z","timestamp":1760159659000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1660-4601\/18\/3\/988"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,1,22]]},"references-count":62,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2021,2]]}},"alternative-id":["ijerph18030988"],"URL":"https:\/\/doi.org\/10.3390\/ijerph18030988","relation":{},"ISSN":["1660-4601"],"issn-type":[{"value":"1660-4601","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,1,22]]}}}