Just four doses of a commonly-used antibiotic could save the lives of thousands of children under the age of five in sub-Saharan Africa, a study led the University of California San Francisco has found.

The researchers looked at the effect of giving the antibiotic azithromycin twice a year to more than 97,000 children aged between one month and five years in Niger, Malawi and Tanzania during a two-year period. An additional 93,00 children were in a control group.

Every year 5.6 million children – mostly in Africa – die before their fifth birthday, many as a result of preventable diseases such as pneumonia, diarrhoea and malaria. Diarrhoea alone accounts for the deaths of 480,000 children a year.

The study, funded by the Bill and Melinda Gates Foundation, discovered the mortality rate among children in communities given the antibiotic was 14 per cent lower than those who received a placebo instead.

Of the three countries included in the study, the biggest falls in mortality were seen in Niger – which has the highest child mortality rate of the three. One in ten children in Niger - 108 children of each 1,000 who are born - die before reaching age five.