Response of children in Bangladesh to adult-type tetanus-diphtheria toxoid (Td) administered during a field trial of cholera toxoid

Abstract

A field trial of cholera toxoid in Bangladesh in 1974–75 presented a unique opportunity to study the antitoxin response to Td administered as a control product. In this population, naturally acquired immunity to diphtheria is developed early in life, making it possible to assess only the booster response to the reduced Lf dosage of diphtheria toxoid in Td. Primary diphtheria immunization could not be evaluated, even in the 1–6 year age group, because of natural immunosensitization. In contrast, a high rate of tetanus susceptibility was encountered, in keeping with low levels of immunization in the population and absence of naturally acquired immunity to this disease. A satisfactory primary immune response to the tetanus toxoid component of Td was demonstrated in 96% of susceptible individuals.