The World Health Organization said the findings could significantly change the way the illness is managed in developing countries.

The research, conducted in Pakistan by researchers from the Boston University School of Public Health, involved 2,037 children with severe pneumonia who were randomly assigned to get either injectable antibiotics in a hospital or antibiotic pills at home. Of the five children who died during the study, four were in the hospitalized group and one was at home.

The WHO said pneumonia is the largest single killer of children under 5 around the world. About 60 percent of pneumonia cases in the developing world are caused by bacteria and can be treated with antibiotics, while most cases of pneumonia in developed countries are viral.

"The potential impact of these results is enormous," said co-author Dr. Shamim Qazi of the WHO. "Being able to treat children with severe pneumonia safely and effectively in their own homes would be of huge benefit to both families and health systems, by reducing the need for admission to hospital."