title: Efficacy of a travelers' diarrhea vaccine system in travelers to India.
abstract: BACKGROUND
  A patch vaccine containing heat-labile toxin (LT) from enterotoxigenic Escherichia coli (ETEC) has demonstrated to be beneficial in reducing the rate and severity of travelers' diarrhea in Latin America. To evaluate the efficacy of this transdermal vaccine system in an area with a different diarrheal pathogen profile, an additional phase 2 study was conducted in European travelers to India.
  
  
  METHODS
  For this multicenter, randomized, double-blinded, placebo-controlled field study 723 subjects were recruited; 603 (299 LT vaccine, 304 placebo) were included in the per-protocol-population (PPP).
  
  
  RESULTS
  Although the LT patch induced a measurable LT immune response in recipients, it failed to protect against LT ETEC or all-cause diarrhea. In the PPP the incidence rate of diarrhea as per primary endpoint was 6.0% (18 of 299) in the vaccine group and 5.9% (18 of 304) in the placebo group. Additionally, lower than expected rates of LT ETEC diarrheas were observed in India. The vaccine delivery system frequently produced rash and pruritus at the site of application, long term hyperpigmentation persisted in a minority of LT recipients, and also few site reactions were noted in the placebo group.
  
  
  CONCLUSIONS
  The evaluated patch vaccine failed to satisfy mainly with respect to protective efficacy. Noninvasive prophylactic agents against travelers' diarrhea, particularly vaccines against the most frequent pathogens, thus continue to be badly needed.
authors.affiliation: Division of Epidemiology and Prevention of Communicable Diseases, Institute of Social and Preventive Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Robert
authors.initials: R
authors.lastname: Steffen
authors.forename: Jakob P
authors.initials: JP
authors.lastname: Cramer
authors.forename: Gerd
authors.initials: G
authors.lastname: Burchard
authors.forename: Tomas
authors.initials: T
authors.lastname: Jelinek
authors.forename: Ute
authors.initials: U
authors.lastname: Schwarz
authors.forename: Prabhugaunker
authors.initials: P
authors.lastname: Ramdas
authors.forename: Santanu
authors.initials: S
authors.lastname: Chatterjee
authors.forename: Zhi-Dong
authors.initials: ZD
authors.lastname: Jiang
authors.forename: Herbert L
authors.initials: HL
authors.lastname: DuPont
authors.forename: Shailesh
authors.initials: S
authors.lastname: Dewasthaly
authors.forename: Kerstin
authors.initials: K
authors.lastname: Westritschnig
authors.forename: Ronald H
authors.initials: RH
authors.lastname: Behrens
mesh_terms: D000279:Administration, Cutaneous; D000293:Adolescent; D000328:Adult; D001428:Bacterial Vaccines / Q000008:administration & dosage*; D003967:Diarrhea / Q000208:ethnology / Q000382:microbiology / Q000517:prevention & control*; D004311:Double-Blind Method; D004926:Escherichia coli / Q000276:immunology*; D004927:Escherichia coli Infections / Q000208:ethnology / Q000382:microbiology / Q000517:prevention & control*; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007194:India / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D014195:Travel; D016896:Treatment Outcome; D006113:United Kingdom / Q000453:epidemiology; D055815:Young Adult
chemical_list: D001428:Bacterial Vaccines