The epidemic is more deadly than the current Ebola outbreak Médecins Sans Frontières (MSF) has told the BBC that very little has been done to combat the measles epidemic in the Democratic Republic of Congo, despite a national epidemic being declared in June.
Karel Janssen, MSF's head of mission in DR Congo, said 23 out of 26 provinces had been affected, but lack of routine vaccination, hygiene, the prevalence of conflict and the high numbers of displaced people had contributed to the spread of the disease.
''An epidemic as this doesn’t suddenly arise; this is also a consequence of years of years of neglect,'' he told BBC Newsday.
“We are facing the biggest measles outbreak that we've seen in more than 10 years in the Congo."
He added that only $2.5m (£2m) has been raised out of the $8.9m required for the health response plan.
More than 2,700 children have died from measles between January and August - that is higher than the total for Ebola in the past year.
Since the beginning of the year, MSF has vaccinated 474,863 children and supported 27,439 patients.
Listen to the full interview with Karel Janssen about the challenges: