TY - JOUR
T1 - Lack of immune response to the Vi component of a Vi-positive variant of the Salmonella typhi live oral vaccine strain Ty21a in human studies
AU - Tacket, Carol O.
AU - Losonsky, Genevieve
AU - Taylor, David N.
AU - Baron, Louis S.
AU - Kopecko, Dennis
AU - Cryz, Stanley
AU - Levine, Myron M.
N1 - Funding Information:
Received 17 May 1990; revised 16 October 1990. Informed consent was obtained from all volunteers, and human experimentation guidelines of the US Department of Health and Human Services and of the University of Maryland School of Medicine were followed. Financial support: US Army contract 17-88-C-8039. Reprints or correspondence: Dr. Carol O. Tacket, Center for Vaccine Development, University of Maryland School of Medicine, 10 S. Pine St., Baltimore, MD 21201.
PY - 1991/4
Y1 - 1991/4
N2 - New typhoid vaccines have been sought to replace the reactogenic parenteral whole cell vaccines. Both Ty21a, a live oral attenuated Vi-negative Salmonella typhi vaccine strain, and parenteral Vi polysaccharide vaccine are safe and efficacious in field trials. To achieve potentially greater protective efficacy, a derivative of Ty21a that expresses Vi polysaccharide was prepared and its safety and immunogenicity assessed in 27 adult volunteers. The volunteers received either one dose of 5 x 105, 5 x 107, or 5 x 109 cfu or three doses of 5 x 109 cfu of lyophilized vaccine and were observed for adverse effects on a research isolation ward. The vaccine was well tolerated; however, at the highest dose, 13% of volunteers had mild diarrhea. Serial blood cultures were negative for the vaccine strain. Vaccine was shed in the stool of most volunteers at the higher doses for 1-4 days. No serum antibodies to Vi, circulating cells secreting antibody to Vi, or jejunal fluid antibodies to Vi were detected in any volunteer.
AB - New typhoid vaccines have been sought to replace the reactogenic parenteral whole cell vaccines. Both Ty21a, a live oral attenuated Vi-negative Salmonella typhi vaccine strain, and parenteral Vi polysaccharide vaccine are safe and efficacious in field trials. To achieve potentially greater protective efficacy, a derivative of Ty21a that expresses Vi polysaccharide was prepared and its safety and immunogenicity assessed in 27 adult volunteers. The volunteers received either one dose of 5 x 105, 5 x 107, or 5 x 109 cfu or three doses of 5 x 109 cfu of lyophilized vaccine and were observed for adverse effects on a research isolation ward. The vaccine was well tolerated; however, at the highest dose, 13% of volunteers had mild diarrhea. Serial blood cultures were negative for the vaccine strain. Vaccine was shed in the stool of most volunteers at the higher doses for 1-4 days. No serum antibodies to Vi, circulating cells secreting antibody to Vi, or jejunal fluid antibodies to Vi were detected in any volunteer.
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U2 - 10.1093/infdis/163.4.901
DO - 10.1093/infdis/163.4.901
M3 - Article
C2 - 2010645
AN - SCOPUS:0025908003
SN - 0022-1899
VL - 163
SP - 901
EP - 904
JO - Journal of Infectious Diseases
JF - Journal of Infectious Diseases
IS - 4
ER -