A new vaccine against a diarrheal disease that kills about 600 children a day worked well in a large trial in Africa and appears to be a practical way to protect millions of children, scientists said on Wednesday.

The new vaccine against rotavirus, the most common cause of death from diarrhea in children under age 5, is made by an Indian company and was tested in Niger by Doctors Without Borders.

The vaccine is expected to be as cheap as or cheaper than current alternatives. More important, it can last for months without refrigeration, which makes it far easier to use in remote villages with no electricity.

It must be approved by the World Health Organization before it can be widely distributed, a process that is underway.