The randomised, placebo-controlled trial was originally scheduled to start in June, but had to be postponed following the H1N1 flu outbreak in Mexico. A total of 1,800 volunteers travelling to Mexico or Guatemala, mainly from the UK and Germany, will be enrolled.
The vaccine is designed to protect against enterotoxigenic E. coli, a major cause of travellers’ diarrhoea. It consists of a self-adhesive patch containing 37.5 micrograms of the heat-labile toxin from the pathogen and a single-use applicator designed to enhance uptake through the skin.
Researchers reported promising results in an earlier Phase II trial of the vaccine. A total of 178 volunteers received two doses of either the vaccine or placebo, two to three weeks apart, before travelling to Mexico or Guatemala.
Results from 170 participants showed that those who received the vaccine were significantly less likely to experience diarrhoea than those who received placebo.
Compared with placebo, the patch reduced the incidence of moderate to severe diarrhoea by 75% (p=0.0070) and the incidence of severe diarrhoea by 84% (p=0.0332). Episodes of diarrhoea were shorter in vaccinated individuals than in those who received placebo (0.5 days vs 2.21 days, p=0.0006), with fewer loose stools (3.7 vs 10.5, p<0.0001).