The Incidence and Trends of Yellow Fever from 1990 to 2021 in Major Endemic Regions: A Systematic Analysis Based on the 2021 Global Burden of Disease Study

As a re-emerging disease, the worldwide burden and trends of yellow fever (YF) remain inadequately quantified. This study aims to assess the incidence of YF both globally and in major endemic regions from 1990 to 2021. Utilizing data from the Global Burden of Disease (GBD) database, we evaluated the burden of YF. We employed an age-period-cohort model to assess the influence of age, period, and cohort on the incidence of YF from 1992 to 2021. A secondary data analysis based on GBD database showed the following: in 2021, there were 86,509 incident cases of YF. Between 1990 and 2021, the number of incident cases decreased by 74.7%, while the age-standardized incidence rate (ASIR) declined at an EAPC of -4.76% (95% confidence interval: -5.10 to -4.42). In 2021, the highest ASIRs of YF were observed in Western Sub-Saharan Africa, Central Sub-Saharan Africa, and Eastern Sub-Saharan Africa. The analysis of age effects indicates that children aged 5-10 years old exhibit the highest incidence rate. Both period and cohort effects demonstrated a decline in morbidity risk. The decomposition analysis identified epidemiological changes as the primary factor contributing to the global reduction in the YF burden. Despite considerable reduction in incidence, YF remains a significant public health threat in Sub-Saharan Africa.