A total of 12 children have died of measles in south-western Tanzania’s Mlele district since December, district commissioner Majid Mwanga has told the BBC.
He added that 847 children had been infected with measles in the district between December and February.
Health workers have so far vaccinated 16,480 children and are continuing with the exercise, Mwanga said.
The government has urged people in the area to abandon false beliefs – such as that their children died after being bewitched – and get them vaccinated.
Five months ago, Tanzania’s Minister of Health Ummy Mwalimu announced the outbreak of measles in seven regions. He started a nationwide campaign to provide vaccinations for measles and rubella to children under the age of five.
People of all ages can get measles, but it mostly affects children under five.
Measles usually starts with cold-like symptoms, followed by a rash a few days later. Some people may also get small spots in their mouth.