The suspected death toll of an ongoing yellow fever outbreak that began in Angola and spread to neighboring Democratic Republic of the Congo has climbed to nearly 400 people, according to WHO.
Hampering control efforts, infections in the two countries — potentially numbering more than 3,500 — are concentrated in large, densely populated cities, which is unusual for yellow fever outbreaks, WHO said.
In Angola, there have been 2,893 suspected cases of yellow fever and 325 deaths since December, according to WHO’s latest situation report. Among these cases, 788 have been laboratory-confirmed. Sixteen of Angola’s 18 provinces have seen confirmed cases, and the other two have reported suspected cases. In Luanda, where the outbreak began, transmission persists despite the vaccination of around eight million people, WHO said.
After declaring the outbreak “a serious public health event” last month, WHO said this week that it still does not consider the outbreak a Public Health Emergency of International Concern — a designation that would likely generate action from countries around the world.
In Democratic Republic of the Congo (DRC), there have been 700 suspected cases and 63 deaths as of May 31, WHO announced in a separate report. Of the cases, 52 have been confirmed, most of them imported from Angola.
“Additional cases of local transmission are to be expected in the country due to the continuous importation of yellow fever cases from Angola, the currently insufficient yellow fever vaccination coverage, ecological factors and high vector density,” WHO said.
The risk for continued spread outside Angola remains a serious concern, according to WHO, especially in normally low-risk countries such as Namibia and Zambia, which share a long and porous border with the country and where the population, travelers and foreign workers are not vaccinated against yellow fever.
Kenya and China also have reported confirmed yellow fever cases imported from Angola, further highlighting the risk of international spread through nonimmunized travelers.
Meanwhile, Uganda has reported cases of yellow fever that are not epidemiologically linked to Angola, and three other countries — Republic of Congo, Sao Tome and Principe, and Ethiopia — have reported suspected cases of yellow fever and investigations are underway to determine if they are linked to the outbreak.
WHO urged countries to bolster their immunization efforts, particularly those with populations of mosquitoes that transmit the virus. Vaccines must be administered at least 10 days before travel to be effective. – by Gerard Gallagher