Hope for a topical vaccine for travellers' diarrhoea
A skin patch containing a vaccine heat labile enterotoxin (LT) to help travellers ward off diarrhoea has been shown to be effective in trials by US researchers.
This was a phase 2 study in which 178 volunteers who planned to travel to Mexico or Guatemala received two patches two to three weeks apart, containing either LT or placebo.
Data on 170 travellers was available for analysis. In the placebo group, 22% had diarrhoea, of which 11% was caused by entero-toxigenic Escherichia coli.
Protective efficacy in the vaccinated group was 75% for moderately severe diarrhoea and 84% against severe diarrhoea. Vaccinated recipients had shorter episodes of diarrhoea and fewer loose stools.
Antibiotic use was twice as frequent in the placebo group so LT patch efficacy may be even greater than was shown by this study.
This vaccination route was safe, but those vaccinated with the LT patch were much more likely to experience pruritus or rash than those on placebo.
The results of a much larger phase 3 study are awaited.
Frech SA, DuPont HL, Bourgeous AL et al. Use of a patch containing a heat labile toxin from Esherichia coli against travellers¹ diarrhoea: a phase 2, randomised double blind, placebo-controlled field trial. Lancet