ABSTRACT
Aims: The aim of this study is to investigate the timeliness and out-of-sequence vaccination among children aged less than five years through the data of a local Health and Demographic Surveillance System (HDSS) in Burkina Faso. Study Design: Cross-sectional study nested into an existing HDSS. Place and Duration of Study: Nouna Health District in north-western Burkina Faso, over the period of September 2008 to December 2009. Methodology: We used data of 7,644 children born between September 2003 and March 2009. Vaccination data were provided on the basis of events recorded on vaccination cards. We assessed vaccination timeliness and the frequency of out-of-sequence vaccination. Results: The highest rates of timely administration were observed with vaccines recommended at birth (e.g. 68% for BCG) while the lowest rates were observed with vaccines given in late infancy (e.g. 33% for measles). The frequency of out-of-sequence vaccination between BCG and DTP/Penta 1 or between DTP/Penta 3 and measles were respectively around 5% and 4%. Out-of-sequence vaccination in early infancy occurred significantly more frequent in rural compared to urban areas contrary to out-of-sequence vaccination in late infancy. Both, timely and correct sequencing of vaccination have significantly improved in recent years in the study area. Conclusions: This study supports that significant vaccination delay occurs in SSA communities with high vaccination coverage and that the frequency of out-of-sequence vaccinations varies substantially between countries.