Studies of combined quadruple vaccines against diphtheria, pertussis, tetanus, and typhoid fever: reactogenicity and antigenicity.

Different DPT + typhoid vaccines were produced by two laboratories and tested in the field for untoward local or systemic reactions and in the laboratory for immunogenic properties. The combined DPT and acetone-inactivated and dried typhoid antigen was found to cause more numerous and more severe local and systemic reactions than the DPT and DPT + typhoid (heat-thiomersal) vaccines. The antibody responses to all four antigens in both of the combined DPT + typhoid vaccines were very satisfactory.From the results of these studies it is concluded that quadruple DPT + typhoid vaccine is suitable for use in areas where typhoid fever is a problem and where logistic and other considerations require the use of combined vaccines.