A Saudi Arabian charitable foundation says it will give $US50 million ($A66 million) to the United Nations children's agency to help eliminate measles, the largest private donation ever to UNICEF's efforts.
The donation by Riyadh-based Alwaleed Philanthropies comes amid rising concern about the highly contagious disease, a leading cause of death among children, with recent outbreaks in Italy and Romania.
It will help vaccinate more than 51 million children in 14 countries, UNICEF said.
Anthony Lake, UNICEF's head, said the show of charity could inspire others to give to the immunisation effort.
"Alwaleed Philanthropies' generosity will ... serve as a catalyst to spur greater investment," he said in a statement.
The gift is the largest single private donation ever made to UNICEF's measles and rubella elimination efforts, a UNICEF spokeswoman said.
According to the World Health Organisation (WHO), the virus can lead to deadly complications like diarrhoea, dehydration, respiratory infection and encephalitis and kills nearly 400 children every day.
It can be prevented with two doses of a widely available and inexpensive vaccine but continues to infect tens of thousands of people globally.
Reported measles cases increased in Africa, Europe and the Eastern Mediterranean region in 2014 and 2015, according to WHO.
