Effectiveness of a trivalent serogroup A/CIW135 meningococcal polysaccharide vaccine in Burkina Faso, 2003

Following a large Neisseria meningitidis W 135 (NmW135) epidemic in Burkina Faso (BF) during 2002, a newly licensed trivalent A/C/W135 meningococcal polysaccharide vaccine was introduced in 2003. We conducted a case-control study to assess the vaccine effectiveness (VE) against meningococcal disease. Thirty-two N. meningitidis A (NmA) and 3 NmW135 meningitis cases were enrolled and matched by age-neighborhood to 103 controls. After adjusting for confounding risk factors, VE against NmA or NmW135 was 83.6% (95% CI 31.8-97.0, p =0.01) for persons with verified vaccination. VE against probable/definite NmA alone was 94.0% (95% CI 58.7-99.0, p=0.0003). Low number of NmW135 cases did not allow estimation of VE against NmW 135 alone. The vaccine was highly effective against the epidemic. Since 2003, the trivalent vaccine continues to be effectively used in Africa for the control of meningococcal disease epidemics. (C) 2007 Elsevier Ltd. All rights reserved.