Safety and immunogenicity of WRSd1, a live attenuated Shigella dysenteriae type 1 vaccine candidate.

Among Shigella serotypes Shigella dysenteriae type 1 produces the most severe disease, including cases of hemolytic-uremic syndrome and pandemic outbreaks. WRSd1 is a live S. dysenteriae 1 strain attenuated by deletion of the virG(icsA) gene, which encodes a protein that mediates intercellular spread, and stxA and stxB, which encode the Shiga toxin.

Transcutaneous immunization with the heat-labile toxin (LT) of enterotoxigenic Escherichia coli (ETEC): protective efficacy in a double-blind, placebo-controlled challenge study.

Background: An enterotoxigenic Escherichia coli (ETEC) vaccine could reduce diarrhea among children in developing countries and travelers to these countries. The heat-labile toxin (LT) of ETEC is immunogenic but too toxic for oral or nasal vaccines.

Methods: In a double-blind, placebo-controlled trial, 59 adults were randomized to receive 50 microg of LT or placebo in a patch applied to alternating arms on days 0, 21, and 42.