Effect of COVID-19 vaccination coverage on transmission and mortality during Omicron dominance

Background: During the coronavirus disease 2019 (COVID-19) pandemic, the emergence of the Omicron SARS-CoV2 variant raised concerns about reduction in vaccine effectiveness due to its higher transmissibility. Thus, using ecologic data, we assessed the population-level impact of COVID-19 v...

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Main Authors: Stephen Chukwuma Ogbodo, Joseph Junior Damba, Omotayo Olaoye, Divine-Favour Chichenim Ofili, Adaeze Augustina Ngwu
Format: Article
Language:English
Published: Academia.edu Journals 2025-02-01
Series:Academia Medicine
Online Access:https://www.academia.edu/127848516/Effect_of_COVID_19_vaccination_coverage_on_transmission_and_mortality_during_Omicron_dominance
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author Stephen Chukwuma Ogbodo
Joseph Junior Damba
Omotayo Olaoye
Divine-Favour Chichenim Ofili
Adaeze Augustina Ngwu
author_facet Stephen Chukwuma Ogbodo
Joseph Junior Damba
Omotayo Olaoye
Divine-Favour Chichenim Ofili
Adaeze Augustina Ngwu
author_sort Stephen Chukwuma Ogbodo
collection DOAJ
description Background: During the coronavirus disease 2019 (COVID-19) pandemic, the emergence of the Omicron SARS-CoV2 variant raised concerns about reduction in vaccine effectiveness due to its higher transmissibility. Thus, using ecologic data, we assessed the population-level impact of COVID-19 vaccination coverage on COVID-19 transmission and mortality, during the period of Omicron dominance globally. Subject and methods: We used a longitudinal dataset of 110 countries over 16 months (January 2022 to April 2023). Applying random-effects regression models, we assessed the effect of monthly full vaccination coverage on the rates of newly confirmed COVID-19 cases and deaths, adjusting for country characteristics. We obtained the data from open-access databases, including the World Health Organization (WHO) COVID-19 Dashboard and the Oxford COVID-19 Government Response Tracker. Results: On average, each 1% point increase in full vaccination coverage was associated with a 1.4% reduction (95% confidence interval (CI): 0.1%–2.8%, p = 0.035) in the rate of new cases and a 5% reduction (95% CI: 3.6%–6.4%, p < 0.001) in the rate of deaths. This protective effect of vaccination was graded across the levels of vaccination coverage: compared to countries with <50% vaccination coverage, those with coverages of 50%–59%, 60%–69%, 70%–79%, and ≥80% had 20.5% (95% CI: –16.4%–45.7%), 53.8% (22.6%–72.5%), 54.3% (15.5%–75.3%), and 69.6% (38.7%–84.9%) lower rates of new cases, respectively, on average. Conclusions: Our findings suggest an important role of vaccination in mitigating the impact of pandemics, particularly despite the emergence of highly transmissible variants like Omicron.
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spelling doaj-art-698d88de491c441d9800b793504b2af42025-08-20T03:08:46ZengAcademia.edu JournalsAcademia Medicine2994-435X2025-02-012110.20935/AcadMed7536Effect of COVID-19 vaccination coverage on transmission and mortality during Omicron dominanceStephen Chukwuma Ogbodo0Joseph Junior Damba1Omotayo Olaoye2Divine-Favour Chichenim Ofili3Adaeze Augustina Ngwu4Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, H3A 0G4, Quebec, Canada.Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, H3A 0G4, Quebec, Canada.Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, H3A 0G4, Quebec, Canada.Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, H3A 0G4, Quebec, Canada.Department of Pharmacology, Faculty of Veterinary Medicine, University of Nigeria, Nsukka, 410001, Enugu State, Nigeria. Background: During the coronavirus disease 2019 (COVID-19) pandemic, the emergence of the Omicron SARS-CoV2 variant raised concerns about reduction in vaccine effectiveness due to its higher transmissibility. Thus, using ecologic data, we assessed the population-level impact of COVID-19 vaccination coverage on COVID-19 transmission and mortality, during the period of Omicron dominance globally. Subject and methods: We used a longitudinal dataset of 110 countries over 16 months (January 2022 to April 2023). Applying random-effects regression models, we assessed the effect of monthly full vaccination coverage on the rates of newly confirmed COVID-19 cases and deaths, adjusting for country characteristics. We obtained the data from open-access databases, including the World Health Organization (WHO) COVID-19 Dashboard and the Oxford COVID-19 Government Response Tracker. Results: On average, each 1% point increase in full vaccination coverage was associated with a 1.4% reduction (95% confidence interval (CI): 0.1%–2.8%, p = 0.035) in the rate of new cases and a 5% reduction (95% CI: 3.6%–6.4%, p < 0.001) in the rate of deaths. This protective effect of vaccination was graded across the levels of vaccination coverage: compared to countries with <50% vaccination coverage, those with coverages of 50%–59%, 60%–69%, 70%–79%, and ≥80% had 20.5% (95% CI: –16.4%–45.7%), 53.8% (22.6%–72.5%), 54.3% (15.5%–75.3%), and 69.6% (38.7%–84.9%) lower rates of new cases, respectively, on average. Conclusions: Our findings suggest an important role of vaccination in mitigating the impact of pandemics, particularly despite the emergence of highly transmissible variants like Omicron.https://www.academia.edu/127848516/Effect_of_COVID_19_vaccination_coverage_on_transmission_and_mortality_during_Omicron_dominance
spellingShingle Stephen Chukwuma Ogbodo
Joseph Junior Damba
Omotayo Olaoye
Divine-Favour Chichenim Ofili
Adaeze Augustina Ngwu
Effect of COVID-19 vaccination coverage on transmission and mortality during Omicron dominance
Academia Medicine
title Effect of COVID-19 vaccination coverage on transmission and mortality during Omicron dominance
title_full Effect of COVID-19 vaccination coverage on transmission and mortality during Omicron dominance
title_fullStr Effect of COVID-19 vaccination coverage on transmission and mortality during Omicron dominance
title_full_unstemmed Effect of COVID-19 vaccination coverage on transmission and mortality during Omicron dominance
title_short Effect of COVID-19 vaccination coverage on transmission and mortality during Omicron dominance
title_sort effect of covid 19 vaccination coverage on transmission and mortality during omicron dominance
url https://www.academia.edu/127848516/Effect_of_COVID_19_vaccination_coverage_on_transmission_and_mortality_during_Omicron_dominance
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