MenAfriVac as an antitetanus vaccine

Background. The group A meningococcal conjugate vaccine, PsA-TT, uses tetanus toxoid (TT) as a carrier protein (PsA-TT). TT as a carrier protein in other conjugate vaccines is known to be immunogenic and generates a robust anti-TT response. Methods. Clinical studies in Africa assessed whether PsA-TT generated tetanus serologic responses when tested in African populations (toddlers to adults). Second, the high acceptance of PsA-TT mass immunization campaigns in the 1- to 29-year age group meant that a sizeable fraction of women of reproductive age received PsA-TT. Incidence data for neonatal tetanus were reviewed for countries with and without PsA-TT campaigns to check whether this had any impact on the incidence. Results. PsA-TT generated robust tetanus serologic responses in 1- to 29-year-olds, similar to those expected after a booster dose of TT. Neonatal cases of tetanus fell by 25% in countries that completed PsA-TT campaigns in 1- to 29-year-olds. Conclusions. Although these data are not yet definitive, they are consistent with the hypothesis that improved community immunity to tetanus as a result of the PsA-TT campaigns may be having an impact on the incidence of neonatal tetanus in sub-Saharan Africa.