• T M Yaméogo, J G Breugelmans, J L Kambou, O Badolo, S Tiendrebéogo, E Traoré, F Avokey, and S Yactayo.
• Agence de Médecine Préventive, Bobo Dioulasso, Burkina Faso. tene_yam@yahoo.fr
• Med Trop (Mars). 2009 Aug 1; 69 (4): 320-1.

AbstractYellow fever (YF) remains a public health problem in Africa. In 2007 and 2008, Togo, Senegal, Mali and Burkina Faso became the first countries to implement mass YF immunization campaigns within the framework of the Yellow Fever Initiative. The goal of this initiative led by the World Health Organization (WHO) and the United Nations Children's Fund (UNICEF) with the support of The Global Alliance for Vaccines and Immunization (GAVI) is to organize mass YF immunization campaigns in 12 African countries at high risk forYF transmission between 2006 and 2013. A total of 290 million USD have been allocated for vaccination of 180 million people with the highly effective attenuated 17DYF vaccine. Working in partnership with the WHO, the 12 member states are to identify and target high risk areas with the dual aim of preventing epidemics and increasing immunization coverage. Surveillance of adverse events following immunization (AEFI) is a mandatory component for organization of these campaigns. Purpose. The purpose of this article is to describe the AEFI surveillance system implemented in Burkina Faso in 2008. Methods. The strategy used in Burkina Faso was based on a combination of regular passive surveillance and active surveillance. General guidelines and related operational processes were established including reporting forms, investigation forms, and procedures for collection, storage and transport of biological specimens. Classification of cases was based on clearly defined criteria. Any patient meeting the defined criteria and requiring hospitalization was considered as a serious case. In addition to case definition criteria, serious cases were tracked according to presented signs and symptoms using a line-listing form at two university hospital centers in Ouagadougou and one regional hospital center. Emergency room admission records and patient charts were examined during the surveillance period (30 days after the end of the immunization campaign) and on-duty hospital staff were interviewed. The Ministry of Health appointed an 11-member National Expert Committee (NEC) to investigate and judge the status of reported cases. After eliminating coincidental events, program errors, and undetermined cases, vaccination was established as the suspected cause. Suspected cases were classified as viserotrophic or neurotrophic AEFI and recorded as probable cases pending confirmation by virologic studies. An AEFI center with a duly mandated coordinator was designated to coordinate the activities of the different teams involved and to serve as an interface for the expert committee. Detection and investigation teams were formed at each of the hospital locations. A national laboratory as well as an international virology laboratory were designated as reference centers for performance of further testing. Results. Between November 28, 2008, and December 9, 2008, a total 7,566,218 people (aged 9 months and older) excluding pregnant women, critically ill patients, and individuals allergic to eggs, were immunized in 37 of the 63 districts in Burkina Faso. Administrative vaccination coverage was 102.3%. Systematic line-listing at the 3 hospital centers accounted for most of the suspected serious AEFIs identified from reported cases. During the AEFI surveillance period, the NEC met once a week to discuss the suspected serious AEFI. Some cases were excluded and others were designated for further testing. At least one biological specimen was available for all retained cases. Each case benefited from laboratory testing to achieve differential clinical diagnosis as well as from virological testing (results pending). Conclusion. Experiences in Burkina Faso demonstrates the value of active surveillance and of systematic line listing. However, the duration of case investigation and data management was at least six months. To improve AEFI surveillance in future campaigns, several measures can be recommended. Planning should begin well in advance with appropriate funding. Training should be given to raise awareness at all levels of the health system. Mechanisms should be developed for systematic and timely collection and processing of biological samples and data at national level.

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