Estimation of yellow fever incidence in Togo between 2010 and 2020

Yellow fever virus is an arbovirus transmitted to humans by Aedes and Haemogogus mosquito species. To date, there is no specific treatment for yellow fever. However, an effective vaccine is available for the prevention. After a decline in yellow fever cases in Africa between 2004 and 2015, large-scale transmission of the virus was observed in Africa during 2019, with outbreaks recorded in West Africa. The objective of this study was to estimate the incidence of yellow fever cases recorded in the national reference laboratory of Togo from 2010 to 2020.

Data were extracted from the National Institute of Hygiene database from 2010 to 2020 with an Excel sheet and descriptive analyses were performed.

A total of 4350 samples were collected between 2010 and 2020 in Togo from yellow fever suspected cases. These cases had a median age of 12 years (IQR: 5-24), and 21% of them were from the Maritime region. Among them, 30 cases were reported by national laboratory, with a global incidence of 0.7% (confidence interval 95%: [0.4-1.0]). At the yellow fever regional laboratory, 14 cases were confirmed with an incidence of 0.33% (confidence interval 95%: [0.18-0.55]). In this population, 37.7% had been immunized against yellow fever.

This study shows that Togo presents cases of yellow fever. Identification of the vectors and implementation of efficient vector control measures could help prevent this disease, as well as other diseases transmitted by the same vectors. Yellow fever vaccination should be a priority in vaccination programs.