Yellow fever outbreak 'serious public health event,' WHO says

The outbreak of yellow fever in central Africa is serious situation that needs to be controlled better, the World Health Organization says.

Yellow fever is named after the jaundice that affects some patients.

Since December, there have been 2,267 suspected cases in Angola and 296 deaths, according to the WHO.

In this outbreak, the infection is spread by the Aedes aegypti mosquito, which also transmits Zika and dengue viruses.

In Angola, the fear is the outbreak, centred in Luanda, will continue to spread. Travellers from Angola have already brought cases to Congo, China and Kenya.

"The urban yellow fever outbreaks in Angola and the Democratic Republic of the Congo is a serious public health event which warrants intensified national action and enhanced international support," the World Health Organization's emergency committee said Thursday. 

WHO's director-general accepted the group's assessment that the event currently falls short of a global health emergency.

'Potential for explosive spread'

Dr. Bruce Aylward, interim executive director of the outbreaks and health emergencies cluster at WHO, said the meeting was called because of concern about spread in Angola's capital, Luanda, and Congo's capital Kinshasa, as well as questions about managing the global vaccine supply.

"Urban yellow fever is a particularly dangerous and concerning situation because of both the potential for explosive spread in urban settings with high mortality and also the risk for international spread," Aylward told reporters.

There is an effective preventative vaccine to protect people against yellow fever and vaccine manufacturers are working on increasing the number of doses available. 

It's hoped that by getting vaccination coverage up quickly during the outbreak, it will be curtailed. 

The vaccine costs WHO about $1 a dose. One shot usually offers lifetime protection against the infection.

Most people infected with yellow fever virus have no illness or only mild illness. Symptoms include sudden onset of fever, headache, muscle pain, back pain, nausea, vomiting and fatigue. About 15 per cent of those infected develop the more severe form with high fever, jaundice and organ failure, the U.S. Centers for Disease Control and Prevention says.

China has had 11 imported cases from workers in Angola who returned home but there haven't been any such imported cases in the last month and no further transmissions, Aylward said.

WHO urged countries to enforce vaccine requirements for travellers going into and out of Angola and Congo.  

There is no specific antiviral drug to treat yellow fever infections but care for dehydration, liver and kidney failure, and fever helps.