Meningococcal Seroepidemiology 1 Year After the PsA-TT Mass Immunization Campaign in Burkina Faso

Abstract

Background. A group A meningococcal (MenA) conjugate vaccine, PsA-TT (MenAfriVac), was introduced in Burkina Faso via mass campaigns between September and December 2010, targeting the 1- to 29-year-old population. This study describes specific antibody titers in the general population 11 months later and compares them to preintroduction data obtained during 2008 using the same protocol.Methods. During October–November 2011, we recruited a representative sample of the population of urban Bobo-Dioulasso aged 6 months to 29 years, who underwent standardized interviews and blood draws. We assessed anti-MenA immunoglobulin G (IgG) concentrations (n = 200) and, using rabbit complement, serum bactericidal antibody (SBA) titers against 2 group A strains: reference strain F8238 (SBAref) (n = 562) and strain 3125 (SBA3125) (n = 200).Results. Among the 562 participants, 481 (86%) were aged ≥23 months and had been eligible for the PsA-TT campaign. Among them, vaccine coverage was 86.3% (95% confidence interval [CI], 82.7%–89.9%). Prevalence of putatively protective antibodies among vaccine-eligible age groups was 97.3% (95% CI, 95.9%–98.7%) for SBAref titers ≥128, 83.6% (95% CI, 77.6%–89.7%) for SBA3125 ≥128, and 84.2% (95% CI, 78.7%–89.7%) for anti-MenA IgG ≥2 µg/mL. Compared to the population aged 23 months to 29 years during 2008, geometric mean titers of SBAref were 7.59-fold higher during 2011, 51.88-fold for SBA3125, and 10.56-fold for IgG.Conclusions. This study shows high seroprevalence against group A meningococci in Burkina Faso following MenAfriVac introduction. Follow-up surveys will provide evidence on the persistence of population-level immunity and the optimal vaccination strategy for long-term control of MenA meningitis in the African meningitis belt.

Initial validation of a simulation model for estimating the impact of serogroup A Neisseria meningitidis vaccination in the African meningitis belt

“…[ 23 , 24 ] However, some studies suggest that SBA titers against the vaccine reference strain may not correlate with clinical protection against other NmA strains, and alternate serologic indicators of vaccine-induced immunity may be needed. [ 31 , 32 ] If vaccine-strain SBA does not cross-protect against other strains, VE could decrease over time as new NmA strains emerge. To allow for this possibility, we repeated all analyses with the Updated Vaccination-Plus model assuming fast waning from the Vaccinated state (mean duration of protection, 4.6 years).…”

Comparison of school based and supplemental vaccination strategies in the delivery of vaccines to 5-19 year olds in Africa - a systematic review

“…SIAs: Twelve studies reported vaccination coverage for SIAs. Three studies reported coverage data on meningococcal serogroup A (PsA-TT) vaccine 29 , 30 , 44 , five on measles vaccine 31 , 32 , 34 , 56 , 57 and two on yellow fever vaccine 36 , 43 . Each of the remaining two studies reported on one vaccine; cholera 38 and meningococcal bivalent polysaccharide A/C vaccine 46 .…”

Health workers’ perceptions and challenges in implementing meningococcal serogroup a conjugate vaccine in the routine childhood immunization schedule in Burkina Faso

“…4 Davycas International, Ouagadougou, Burkina Faso. 5 Ministère de la Santé, Ouagadougou, Burkina Faso. 6 UNICEF, New York, NY 10017, USA.…”

“…Infected persons usually experience sudden onset of high fever, neck stiffness, confusion, nausea, and vomiting; about half will die without prompt medical treatment [4]. To help reduce the meningococcal meningitis burden in endemic African countries, meningococcal serogroup A conjugate vaccine (MACV, MenAfriVac™) was introduced beginning in 2010 through mass vaccination campaigns for people from age 1 to 29 years [5]. The incidence of serogroup A meningitis declined sharply following MACV mass vaccination campaigns in these countries, including Burkina Faso [6].…”