A review of the 1992-1993 Yellow Fever outbreak in Kenya and future management options

In 1992-1993 Kenya saw its first outbreak of yellow fever in 50 years in the Rift Valley Province. By March 1993, 55 cases of suspected yellow fever were identified, with 34 deaths. This is likely to be an underestimate of infected cases. This has immeasurable impact on the villages of the region, and economic repercussions for the nation. This report examines the management of the outbreak. Following identification of the causative agent, a mass vaccination campaign and follow-up surveillance was initiated. However, more prompt action could have led to earlier detection of the emerging infection and perhaps limited its extent. There was considerable delay in responding to the initial reports of an unknown haemorrhagic fever. The initial surveillance system omitted a key hospital in the affected region where cases had presented earlier and there was little effort to control the vector mosquito, Aedes africanus. A more efficient reporting and response system may have allowed for earlier recognition of the emerging epidemic. A greater awareness of the clinical syndrome of yellow fever and appropriate early collection of samples for diagnostic confirmation would facilitate the public health response. An education campaign on mosquito avoidance and control could have been directed at the immediate at-risk population. Reliance on an emergency mass vaccination campaign, driven by economic factors in impoverished nations, may allow for temporary control, but sub-optimal immunisation rates allow the opportunity for future outbreaks.