Immunity to tetanus in male adults in Dar es Salaam, Tanzania

Objective: To determine immunity to tetanus in male blood donors with previous diphtheriapertussis- tetanus (DPT)/tetanus toxoid (TT) vaccination. Design: A cross sectional study, conducted in September 1999. Setting: Blood bank, Muhimbili Medical Centre, Dar es Salaam, Tanzania. Methods: Using an antigen competition ELISA technique, serum tetanus anti-toxin levels in two hundred male blood donors were determined. Results: Vaccination history was absent in 43 (21.5%) blood donors, whereas 60 (30%) and 97 (48.5%) reported childhood DPT and TT vaccination, respectively. Tetanus anti-toxin was undetectable in 47 (23.5%) blood donors and the levels were below that considered protective (>>0.1 IU/ml) in 25 (12.5%). Among those with undetectable level, 43 (91.5%) had no vaccination history. Time after last DPT/TT vaccination correlated significantly with tetanus anti-toxin levels (r2=-0.331, p=0.001). In multivariate analysis, TT doses received and time after last vaccination explained 4.8% and 29.4%, respectively, of the variations in tetanus anti-toxin levels. Conclusion: Seventy two (36%) male blood donors were susceptible to tetanus and the susceptibility was highest from 48 years. A regular TT booster dose at 10 yearly intervals is recommended to provide adequate and long lasting immunity in male adults. Proper keeping of vaccination records is emphasised. (East African Medical Journal: 2002 79(2): 73-76