Neonatal Tetanus Immunity in Nigeria: The Effect of HIV Infection on Serum Levels and Transplacental Transfer of Antibodies

Background. Tetanus toxoid immunisation of pregnant mother has remained the most effective strategy in eliminating neonatal tetanus. Impaired production and/or transplacental transfer of antibodies may affect the effectiveness of this strategy. We studied the effect of maternal HIV infection on serum levels and transplacental transfer of anti-tetanus antibodies. Methods. A total of 162 mother-baby paired serum samples were taken and analysed for anti-tetanus antibody levels using ELISA. Maternal HIV status was also determined by double ELISA technique. Maternal TT vaccination status was also documented. Results. Thirty-eight (23.5%) mothers and 41 (25.3%) babies were seronegative, out of whom 8 mothers were HIV positive and 9 babies were HIV exposed. HIV infected mothers and HIV exposed infants were, respectively, 16.27 times (OR = 16.27, 95% CI = 3.28 to 80.61) and 33.75 times (OR = 33.75, 95% CI = 4.12 to 276.40) more likely to be seronegative for anti-tetanus antibody. Similarly, HIV positive mother-newborn pairs were 7.46 times more likely to have a poor transplacental transfer of tetanus antibodies (OR = 7.46, 95% CI = 1.96 to 28.41). Conclusions. Maternal HIV infection is associated with impaired maternofoetal transfer of anti-tetanus antibodies and seronegativity among mothers and their newborns. Hence, this may hinder efforts to eliminate neonatal tetanus.