Descriptive Characterization of Suspected Yellow Fever Cases in Kano state, Nigeria, 2015-2018

INTRODUCTION: Yellow fever remains a serious public health problem globally with an estimated 200, 000 cases annually despite the availability of an effective vaccine for more than 70 years. Nigeria had an outbreak of Yellow fever in 2017 after more than 2 decades of silence. We described the epidemiological characteristic of yellow fever in Kano State from 2015 to 2018. METHODS: We conducted a retrospective review of suspected cases of yellow fever in Kano state from January 2015 to December 2018. A suspected yellow fever case was defined as any person residing in Kano state with sudden onset of fever, with jaundice appearing within two weeks of the onset of the first symptoms from the year 2015 to 2018. We calculated incidences, frequencies and proportions using Microsoft excel 2016 and health mapper version 4.3. RESULTS: A total of 107 patients with suspected yellow fever were reported in the state between 2015 and 2018. The median age of the suspected cases was 13years (range 2-120years) and age group 15-44years had the highest number of cases. More males were affected 69 (64%) with rural local governments having the highest number of patients. Generally, the disease occurred all year round with peaks occurring the wet season mostly in June, July and August. The annual incidence increased from 1.7/1,000,000 populations in 2015 to 2.2/1,000,000 populations in 2016, remained at 2.2/1,000,000 populations in 2017 and slightly decreased to 2.1/1000,000 population in 2018. No mortality was recorded during the reporting period. Majority (99.1%) of the suspected patients had never received yellow fever vaccine. CONCLUSION: The study revealed no change in the incidence rate of suspected Yellow Fever cases in Kano State. Majority of the suspected cases are in the rural areas where immunization coverage was very low. Routine immunization has to be strengthened to address the problem. The findings were reported to the Kano state Ministry of Health for appropriate action.