Health officials battle to contain yellow fever in Africa

The yellow fever outbreak that began in Angola and spread beyond the country’s border has left health officials scrambling to contain the worst outbreak of the disease in decades.

The first incident occurred in December in Viana, a poor suburb of Angola’s capital city, Luanda. Since then, the country has seen more than 3,000 reported cases and more than 340 deaths. The Democratic Republic of Congo, which now has more than a thousand cases, had 53 cases imported from Angola. Two similar cases occurred in Kenya and 11 in China.

“It is vital to interrupt transmission, especially in cross-border areas, to rapidly bring this outbreak under control and halt further international spread,” said Dr. Matshidiso Moeti, the World Health Organization’s regional director for Africa.

Yellow fever is a viral hemorrhagic disease transmitted by infected mosquitoes, primarily the Aedes aegypti. The same mosquito transmits the Zika virus and dengue fever.

International health officials have inoculated more than 5 million people, but many more still need the preventive vaccine for yellow fever. The outbreak has depleted the WHO’s emergency stockpile of 6 million doses of vaccines in Angola alone. By mid-June, WHO had distributed more than 18 million doses between Angola, Congo, and Uganda, where the outbreak is not connected to Angola.

“This has never happened before,” WHO said in a statement. “In the past, the ICG [International Coordinating Group] has never used more than 4 million doses to control an outbreak in one country.”

It takes the manufacturers about 12 months to produce the vaccine. The WHO has enough vaccines in its stockpile to handle the current cases, but it would come up short if the disease spreads any further. In response, the organization recommended this month to dilute the vaccines to one-fifth of the standard. The diluted versions will still protect people for at least a year instead of providing lifelong immunity, WHO explained.

“More research is needed to find out whether fractional doses would be effective in young children who may have a weaker immune response to yellow fever vaccine,” the WHO said in a statement.

The WHO on Thursday said it has planned emergency vaccination campaigns along the border between Angola and Congo in a bid to control broadening transmission. The vaccination efforts also will focus on Congo’s capital, Kinshasa. Congo’s health minister Felix Kabange last week declared the disease an epidemic in Kinshasa and two other provinces.

Doctors Without Borders on Monday said it vaccinated more than 370,000 people in Congo. But the medical aid group also is working to hamper the disease at its roots. The group runs a vector control program in Kinshasa and in the Kongo central province. The program involves working with the local government to educate people on how to get rid of mosquito breeding spaces and chemically spraying the community.

“Our objective is to try to limit the spread of the epidemic,” said Elisabetta Faga, the project coordinator in Kinshasa. “It’s very important even though it’s not the solution for yellow fever.”