An outbreak of yellow fever that's killed 300 people in central Africa is worrying and needs some urgent action — but doesn't amount to a public health emergency at this point, the World Health Organization said Thursday.
Most cases are in Angola, where 2,257 suspected cases are reported. But the virus has been carried by migrant workers to the Democratic Republic of Congo, Uganda and Kenya and 11 travelers have carried it to China.
"The virus in Angola and Democratic Republic of Congo is largely concentrated in main cities," WHO said.
"The risk of spread and local transmission to other provinces in the three countries remains a serious concern. The risk is high also for potential spread to bordering countries especially those classified as low risks for yellow fever disease (i.e. Namibia, Zambia) where the population, travelers and foreign workers are not vaccinated against yellow fever."
WHO's advisory committee met Thursday and decided that the outbreak was slowing, not gaining speed.
"The Committee decided that based on the information provided the event does not at this time constitute a Public Health Emergency of International Concern," WHO said in a statement.
It's advising better surveillance for cases, mass vaccination, mosquito control and other measures, however, to make sure the spread of the virus does not worsen.
Like its cousins Zika, chikungunya and dengue, yellow fever is spread by Aedes mosquitoes. It kills as many as 60,000 people a year. Up to half of those who get severely ill from yellow fever will die without intensive treatment.
There are no specific drugs to treat yellow fever, but good supportive care, such as giving fluids, can help patients survive. And there is a very good, inexpensive vaccine that provides long-term protection.
The current outbreak is potentially explosive, said Dr. Bruce Aylward, executive director for outbreaks and health emergencies at WHO.
"There is no short-term fix for the situation we see with yellow fever," Aylward told reporters.
He said WHO was working with companies that make yellow fever vaccine to build up the current stockpile, and working to vaccinate people at risk. "We are not using (the vaccine) to full effect," he said. He said there should be 7 million doses in the stockpile by the end of the month.