A Cochrane review included two studies with a total of 10 560 subjects. One study (1 919 infants in Columbia) assessed the effectiveness of tetanus toxoid in preventing neonatal tetanus deaths. After a single dose, the relative risk (RR) was 0.57 (95% CI 0.26 to 1.24), and the vaccine effectiveness was 43%. With a two or three dose course, the RR was 0.02 (95% CI 0.00 to 0.30); vaccine effectiveness was 98%. No effect was detected on causes of death other than tetanus. The RR of cases of neonatal tetanus after at least one dose of tetanus toxoid was 0.20 (95% CI 0.10 to 0.40); vaccine effectiveness was 80%. Another study, involving 8 641 children in rural Bangladesh, assessed the effectiveness of tetanus-diptheria toxoid in preventing neonatal mortality after one or two doses. The RR was 0.68 (95% CI 0.56 to 0.82); vaccine effectiveness was 32%. In preventing deaths at 4 to 14 days, the RR was 0.38 (95% CI 0.27 to 0.55), and vaccine effectiveness 62% (95% CI 45% to 73%).
Comment: The quality of evidence is downgraded by imprecise results (few outcome events).