he World Health Organization is attempting to ratchet up attention on a highly concerning yellow fever outbreak in Africa.
The global health agency announced Tuesday it is convening a panel of experts to advise it on whether the outbreak — which started in Angola but has spread from there — meets the criteria to be declared a global public health emergency. The so-called emergency committee will hold its first meeting Thursday, by teleconference.
Some outside experts have been clamoring for the WHO to take this move. Georgetown University’s Dr. Daniel Lucey and Lawrence Gostin, for example, writing in the Journal of the American Medical Association last week, warned that the agency had been late declaring Ebola an emergency and should not repeat the error with yellow fever.
The disease is caused by a virus related to the dengue and Zika viruses and is spread, as they are, by Aedes mosquitoes. But whereas dengue and Zika rarely kill, yellow fever can be fatal in a significant proportion of cases.
For decades the virus has been largely confined to what’s termed a sylvatic cycle, spreading between mosquitoes and monkeys in forests of sub-Saharan Africa and in the Amazon basin. Human cases occur from time to time, but under those circumstances the virus isn’t well adapted to be able to efficiently spread among people.
Experts have warned, however, that with the growth of large cities near places that harbor the virus, urban mosquito pools could become infected and the virus could get better at infecting people.
“It takes awhile for the virus to adapt and take off. That’s apparently already happened in Angola,” Yellow fever expert Duane Gubler told STAT in an interview.
Gubler, who recently retired from the Duke-NUS Medical School in Singapore, sees worrisome signs in the outbreak.
In its most recent update on the Angola outbreak, the WHO had reported 2,267 suspected cases in the country, with 293 deaths. Most of the cases have centered around the capital Luanda.
Experts on the virus have been alarmed by the ongoing outbreak in Angola, warning of the dangers of urban outbreaks of this disease.
People infected in Angola have also travelled to China, Kenya, and the Democratic Republic of Congo, where there now appears to be some local spread of the virus in the Congolese capital of Kinshasa. It has a population of over 10 million people.
Experts have warned that if the virus ignites outbreaks in other large urban settings in Africa and Asia, the world will have a serious crisis on its hands. There is a yellow fever vaccine, and it is highly effective, conferring life-long immunity with a single dose.
But according to Gostin, a health-law and policy specialist, “global supplies of the yellow fever vaccine are dwindling, and we could easily face a critical shortage.”
“The world needs WHO to be a global leader in conserving existing vaccine supplies, deploying them strategically, and developing surge capacity for vaccine production,” Gostin told STAT in an email.
Gubler and other experts have advised the WHO to use fractional doses of the vaccine to stretch supplies. Studies in Brazil have shown that one-fifth of a standard dose is still protective.
“To me, that is a solution for the African situation. And it should be done immediately,” Gubler said.
This is the sixth time the WHO has convened an emergency committee to help it chart its response to a disease outbreak. Previous panels have been established to advise on the H1N1 flu pandemic in 2009, setbacks in the polio eradication campaign, the West African Ebola crisis, and when the viruses responsible for Middle East respiratory syndrome and Zika each emerged.
In four of the five cases, a public health emergency of international concern — a PHEIC in the language of the WHO — was declared. The emergency committee that monitors MERS continues to track the outbreak but has never declared it an emergency.