Sixty-one people have died of meningitis since January in Niger, the United Nations said Tuesday, despite mass vaccinations to prevent a possible epidemic.

A total of 736 cases have been officially recorded this year, the local branch of the UN Office for the Coordination of Humanitarian Affairs said, adding that children under four comprised 30 percent of the total cases.

"From January 4 to March 13, 736 cases of meningitis have been recorded in Niger," OCHA said. These cases included 61 deaths.

Thirty-five percent of the total cases involved children aged between five and 14, it said.

The UN, along with medical charity Doctors Without Borders (MSF) has launched mass vaccination programmes in the affected areas, including the capital Niamey.

The World Health Organization (WHO) had warned in December of a risk of fresh meningitis outbreaks in 2016 in Africa, particularly in Niger and Nigeria, which were both badly hit last year.

The risk was deemed to be specially high in parts of Niger affected by the epidemic in 2015 where the vaccination of people was only partially completed.

Between January and June last year, recorded 573 deaths and over 8,500 cases.