DURATION OF PROTECTIVE IMMUNITY CONFERRED BY MATERNAL TETANUS TOXOID IMMUNIZATION - FURTHER EVIDENCE FROM MATLAB, BANGLADESH

Objectives. Although maternal tetanus immunization has been shown to b e highly effective in the prevention of neonatal tetanus, unresolved q uestions remain concerning the required minimum number of doses and th e resulting duration of effective: immunity. This study examined the d uration of effective immunity against neonatal tetanus provided by mat ernal tetanus immunization. Methods. A randomized, double-blind choler a vaccine trial of 41 571 children and nonpregnant adult women carried out in 1974 in the Matlab comparison area of rural Bangladesh provide d a unique opportunity to address dose and immunity issues. Results. C hildren of women who received either 1 or 2 injections of tetanus toro id experienced 4- to 14-day mortality levels consistently lower than t hose of children of unimmunized mothers. Analysis of neonatal-tetanus- related mortality showed that 2 injections of tetanus toroid provided significant protection for subsequent durations of up to 12 or 13 year s. Conclusions. The data demonstrate that a limited-dose regimen of ma ternal tetanus toroid provides significant and extended protection aga inst the risk of neonatal tetanus death.