(CNN) - More than 4,000 people have died from a measles outbreak in the Democratic Republic of Congo this year, UNICEF, the United Nations' children's agency, said on Wednesday.
There have been 203,179 cases of the preventable illness across the country, and nearly 90% of the 4,096 deaths were children under the age of 5.
"The number of measles cases in DRC this year is more than triple the number recorded for all of 2018. The measles outbreak in DRC has become far deadlier than Ebola, which to date, has taken 2,143 lives," UNICEF said in a statement.
According to the World Health Organization, roughly 95% of a population needs to be vaccinated with two doses of the measles vaccine to ensure herd immunity. In Congo, measles immunization coverage was only 57% in 2018, UNICEF said.
"We're facing this alarming situation because millions of Congolese children miss out on routine immunization and lack access to health care when they fall sick," said Edouard Beigbeder, UNICEF representative in DRC.
"On top of that, a weak health system, insecurity, community mistrust of vaccines and vaccinators and logistical challenges all contribute to a huge number of unvaccinated children at risk of contracting the disease."
UNICEF said it was scrambling to vaccinate more children against measles and rushing life-saving medicines to health centers to help prevent deaths. WHO said last month that it was working with the government in Congo and other groups to launch an emergency campaign to vaccinate 825,000 children.
Measles is highly contagious, spreading through coughing and sneezing. Up to 90% of the people close to the infected person, who are not immune, will also become infected. Unvaccinated young children are at highest risk of measles and its complications, including death, according to WHO.
Congo is currently facing the world's second largest Ebola epidemic on record. Ebola is much less contagious, but has a fatality rate of more than 70%.
WHO reported in August that there had been almost three times as many measles cases in 2019 as had been reported by the same time in 2018. Congo, Madagascar and Ukraine had reported the highest numbers, and major outbreaks were ongoing in Angola, Cameroon, Chad, Kazakhstan, Nigeria, Philippines, South Sudan, Sudan and Thailand. The largest outbreaks are in countries with low measles vaccination coverage.