Conference Abstract | Volume 8, Abstract ELIC202581 (Poster 057) | Published: 01 Aug 2025
Stephen Eghelakpo Akar1,2,3&, William Nwachukwu3, Sunbo Oludare Adewuyi1, Anthony Agbakizua Ahumibe1,2, Iniobong Akanimo3, Oyeladun Okunromade3, Olajumoke Babatunde3, Chikwe Ihekweazu4, Mami Hitachi2, Kentaro Kato2, Yuki Takamatsu5, Kenji Hirayama6, Satoshi Kaneko2
1Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan, 2Department of Eco-epidemiology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan, 3Nigeria Centre for Disease Control and Prevention, Abuja, Nigeria, 4WHO Hub for Pandemic and Epidemic Intelligence, Berlin, Germany, 5Department of Virology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan, 6 School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
&Corresponding author: Stephen Eghelakpo Akar, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan, Email: steve.eghelakpo.akar@gmail.com
Received: 30 May 2025, Accepted: 09 Jul 2025, Published: 01 Aug 2025
Domain: Infectious Disease Epidemiology
Keywords: Yellow fever, epidemiology, viral positivity, factors, Nigeria
©Stephen Eghelakpo Akar, et al. Journal of Interventional Epidemiology and Public Health (ISSN: 2664-2824). This is an Open Access article distributed under the terms of the Creative Commons Attribution International 4.0 License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Cite this article: Stephen Eghelakpo Akar, et al., Epidemiology of Yellow fever in Nigeria: Analysis of climatic, ecological, socio-demographic, and clinical factors associated with viral positivity among suspected cases using national surveillance data, 2017-2023. Journal of Interventional Epidemiology and Public Health. 2025;8(ConfProc5):00201. https://doi.org/10.37432/JIEPH-CONFPRO5-00201
Since its resurgence in 2017, Yellow fever outbreaks have continued to occur in Nigeria despite routine immunization and implementation of several reactive mass vaccinations. Nigeria, Africa’s most populous endemic country, is considered a high-priority country for implementing the WHO EYE strategy.
Of 16777 suspected cases, 8532(50.9%) had laboratory confirmation with overall positivity of 6.9%(585). Predictors of YFV positivity were the Jos Plateau (aOR: 6.12, 95% CI: 4.33-8.71), Derived/Guinea Savanah (aOR: 3.46, 95% CI: 2.58-4.70), and Freshwater/Lowland rainforest ecological zones (aOR: 2.11, 95% CI: 1.54-2.92); dry season (aOR: 1.37, 95% CI: 1.02-1.86); the hot dry or humid (aOR: 3.26, 95% CI: 2.37, 5.03); the 2019 (aOR: 3.85, 95% CI: 2.46, 6.27), 2020 (aOR: 2.90, 95% CI: 1.87-4.70), 2021 (aOR: 3.42, 95% CI: 2.04-5.90), 2022 (aOR: 1.88, 95% CI: 1.01-3.51), and 2023 (aOR: 2.56, 95% CI: 1.35-4.85) epidemic years compared to compared to 2017; third (aOR: 3.08, 95% CI: 2.16-4.49) and fourth (aOR: 5.19, 95% CI: 3.48, 7.86) quarters compared to the second; male sex (aOR: 1.49, 95% CI: 1.24-1.80); age group >= 15 years ((aOR: 1.40, 95% CI: 1.11-1.78) compared to <15 years; working in outdoor ((aOR: 1.46, 95% CI: 1.08-1.99); having travel history (aOR: 1.73, 95% CI: 1.04-2.81); being of unknown vaccination status (aOR: 1.34, 95% CI: 1.02-1.78) compared to being vaccinated; and vomiting (aOR: 1.77, 95% CI: 1.19, 2.60).
Ecological, climatic, and socio-demographic characteristics are drivers of YF outbreaks in Nigeria, and public health interventions need to target these factors to halt local epidemics and reduce the risk of international spread. Inadequate vaccination coverage alone may not account for the recurrent outbreaks of YF in Nigeria.
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