Geneva: At least 922 people have died in a measles outbreak in Madagascar, the majority of them children, the World Health Organisation said on Friday.Since the beginning of the outbreak in September, more than 66,000 people in the African island nation have been infected with the highly contagious virus, the WHO said.

Measles is easily preventable through vaccination. The WHO has launched a campaign in collaboration with local authorities to vaccinate more than 6 million children in Madagascar.

The campaign also includes efforts to educate the population and counter negative perceptions about vaccinations.

In a report released last week, the WHO wrote that the outbreak was “unprecedented” and “occurred in a context of poor performance of routine vaccination.”

That report listed 300 deaths and 53,000 infections. The dramatic increase in such a short time is due to a more complete collection of data in Madagascar, a spokesman said on Friday.

There were 229,000 reported measles cases worldwide in 2018 – double the number of the previous year, according to preliminary WHO figures. WHO experts say the actual number of cases is likely to be many times higher.

The former French colony of Madagascar has a population of about 25 million and is one of the 30 poorest nations in the world, according to the United Nations.