In tests with mice, the vaccine provided immunity against all three pathogens, researchers say.

Researchers say they have designed the first-ever vaccine to deliver a one-two-three punch against the main causes of traveller’s diarrhoea. The approach could help save lives in developing countries, where it’s estimated that three common pathogens kill over 100,000 children under the age of five each year, according to the research published in the journal Vaccine.

The vaccine designed by Mario Monteiro from the University of Guelph in Canada combines proteins from pathogenic E coli with sugars from Shigella and Campylobacter jejuni. All three bugs are major causes of bacterial diarrhoea globally. In tests with mice, the vaccine provided immunity against all three pathogens, researchers said.

No licensed vaccines exist against any of these pathogens, they said. A sugar-based vaccine developed by Monteiro earlier against campylobacter alone is currently undergoing human trials but is still an estimated decade away from potential release.

He said this new three-in-one approach may ultimately overtake that earlier single-target vaccine, although any new vaccine may take decades to test and release. “We’re targeting three pathogens at the same time. Instead of three shots, maybe you only need one,” Monteiro said. Further research is needed to determine the optimum amounts of protein and sugars in the vaccine and to make the vaccine more efficient, he said.