title: Onset and duration of protective immunity in challenged volunteers after vaccination with live oral cholera vaccine CVD 103-HgR.
abstract: CVD 103-HgR is a live oral cholera vaccine that, in phase I and II studies to date, has been well tolerated and immunogenic. In challenge studies of US volunteers conducted 4-5 weeks after vaccination, CVD 103-HgR provided significant protection against experimental cholera due to classical and El Tor Vibrio cholerae O1. To determine the onset and duration of protection, two volunteer challenge studies were conducted: the first, 6 months after vaccination and the second, 8 days after vaccination. In both studies, CVD 103-HgR was 100% protective against diarrhea and significantly reduced the rate of shedding of vibrios after challenge with V. cholerae classical Inaba strain 569B, the virulent parent strain of CVD 103-HgR. Previously vaccinated subjects were less likely than naive controls to develop rises in titer of vibriocidal antibodies after challenge (P = .002), and the mean peak titer of vibriocidal antibodies was less than among controls. CVD 103-HgR can provide homologous protective immunity as soon as 8 days after vaccination and protection can persist for at least 6 months.
authors.affiliation: Department of Medicine, University of Maryland School of Medicine, Baltimore.
authors.forename: C O
authors.initials: CO
authors.lastname: Tacket
authors.forename: G
authors.initials: G
authors.lastname: Losonsky
authors.forename: J P
authors.initials: JP
authors.lastname: Nataro
authors.forename: S J
authors.initials: SJ
authors.lastname: Cryz
authors.forename: R
authors.initials: R
authors.lastname: Edelman
authors.forename: J B
authors.initials: JB
authors.lastname: Kaper
authors.forename: M M
authors.initials: MM
authors.lastname: Levine
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000917:Antibody Formation; D002771:Cholera / Q000276:immunology / Q000517:prevention & control*; D022121:Cholera Vaccines / Q000008:administration & dosage / Q000276:immunology*; D006801:Humans; D014611:Vaccination; D014734:Vibrio cholerae / Q000187:drug effects*
chemical_list: D022121:Cholera Vaccines