TY - JOUR
T1 - Progress in vaccines against typhoid fever
AU - Levine, Myron M.
AU - Ferreccio, Catterine
AU - Black, Robert E.
AU - Tacket, Carol O.
AU - Germanier, Rene
AU - Committee, Chilean Typhoid
N1 - Funding Information:
The field trials of Ty21a in Chile were supported by grants from the World Health Organization and by research contract no. DAMD 17-C-1l15 from the U.S. Army Medical Research and Development Command.
Copyright:
Copyright 2016 Elsevier B.V., All rights reserved.
PY - 1989/5
Y1 - 1989/5
N2 - The widely available heat-phenol-inactivated whole cell typhoid vaccine, which provides -65% protection, has limited usefulness because of the adverse reactions it evokes. In contrast, several new typhoid vaccines promise protection without reactogenicity. Attenuated oral vaccine Ty21a has been evaluated in three field trials of efficacy in Santiago, Chile, involving 530, 000 schoolchildren. Three doses of Ty21a in an enteric-coated formulation given within one week provided 69% efficacy for at least four years. Fewer doses conferred less protection, while adding a fourth dose significantly enhanced protection; increasing the interval between doses did not improve protection. Large-scale vaccination with Ty21a appeared to cause a herd-immunity effect. Ty21a has reached the stage of being a practical tool for public health. With respect to other vaccines, the safety and immunogenicity of an auxotrophic (Arcr−, Pur−) Salmonella typhi mutant (strain 541Ty) has recently been evaluated. Lastly, parenteral purified Vi polysaccharide of S. typhi was safe and immunogenic and provided 64%-72% protection (for at least 17-21 months) in controlled field trials in Nepal and South Africa.
AB - The widely available heat-phenol-inactivated whole cell typhoid vaccine, which provides -65% protection, has limited usefulness because of the adverse reactions it evokes. In contrast, several new typhoid vaccines promise protection without reactogenicity. Attenuated oral vaccine Ty21a has been evaluated in three field trials of efficacy in Santiago, Chile, involving 530, 000 schoolchildren. Three doses of Ty21a in an enteric-coated formulation given within one week provided 69% efficacy for at least four years. Fewer doses conferred less protection, while adding a fourth dose significantly enhanced protection; increasing the interval between doses did not improve protection. Large-scale vaccination with Ty21a appeared to cause a herd-immunity effect. Ty21a has reached the stage of being a practical tool for public health. With respect to other vaccines, the safety and immunogenicity of an auxotrophic (Arcr−, Pur−) Salmonella typhi mutant (strain 541Ty) has recently been evaluated. Lastly, parenteral purified Vi polysaccharide of S. typhi was safe and immunogenic and provided 64%-72% protection (for at least 17-21 months) in controlled field trials in Nepal and South Africa.
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U2 - 10.1093/clinids/11.Supplement_3.S552
DO - 10.1093/clinids/11.Supplement_3.S552
M3 - Article
C2 - 2669099
AN - SCOPUS:0024658246
SN - 1058-4838
VL - 11
SP - S552-S567
JO - Clinical Infectious Diseases
JF - Clinical Infectious Diseases
ER -