Urgent action is needed to combat a yellow fever epidemic in Africa amid signs it is turning into a global health emergency and a severe shortage of the vaccine, academics have warned.
With nearly a billion people at risk from the deadly disease in Africa and Latin America and the danger of an outbreak in Asia, immunologist Professor Daniel Lucey and Lawrence Gostin, a professor in global health law, called on the World Health Organisation (WHO) to declare an emergency saying delays over Ebola had "cost lives".
And they also said that because of the surge in new infectious diseases in recent years – thought to be driven in part by climate change – the world should now set up a permanent committee to decide how to respond as new threats emerge.
Angola is in the grip of its worst yellow fever epidemic since 1986 with more than 250 deaths, and the disease is spreading rapidly – Kenya, Uganda and the Democratic Republic of Congo have all reported cases.
Peru has had at least 20 cases and there have also been several in China after people returned from Angola with the disease.
In an article called A Yellow Fever Epidemic: A New Global Health Emergency? in the journal JAMA, the academics, of Georgetown University in Washington DC, warned: “The looming threat of a severe yellow fever vaccine shortage exists amid epidemics in Africa and potentially in Latin America and Asia.”
Millions of people are due to be immunised as this is the only effective way to protect people against the disease, normally spread by mosquitoes.
But a shortage could “spark a health security crisis” and the WHO should consider reducing the dose to make the vaccine go further “given the world’s vital health security interests”, the academics wrote.
The WHO, they argued, should also “urgently convene an emergency committee to mobilize funds, coordinate an international response, and spearhead a surge in vaccine production”.
“Prior delays by the WHO in convening emergency committees for the Ebola virus, and possibly the on-going Zika epidemic, cost lives and should not be repeated,” they wrote.
“Acting proactively to address the evolving yellow fever epidemic is imperative.”
Since the 17th century there have been sporadic outbreaks of the disease outside its normal range in southern Africa and South America, usually in sea ports.
This happened in Europe in 1730 and 1821, when the UK was affected, and there have also been outbreaks in the US, such as in New Orleans in 1905, Memphis, Tennessee, in 1878 and Philadelphia in 1793.
Yellow fever kills people in a particularly nasty way. It initially causes symptoms such as fever, a significant backache, shivering and vomiting for about three or four days.
But shortly after they seem to recover about 15 per cent of patients are hit by a much worse fever that gives them the jaundice from which the disease gets its name.
They can then start bleeding from the eyes, nose and stomach, with further vomiting and cramps. About half of those who get this more severe strain will die as a result. There is no treatment.
Since the 1980s, the medical community has reported a range of new disease threats, such as Middle East Respiratory Syndrome (MERS), Severe Acute Respiratory Syndrome (SARS), West Nile virus, bird flu and swine flu.
There are thought to be a number of reasons for this, including the growth of the human population coupled with the ease of international travel; the global trade in animals and plants; the loss of natural habitats which has forced animals to look for new places to find food; and climate change, which has enabled animals to move to different places.
Scientists are concerned that yellow fever could reach Britain naturally as the climate gets warm enough for Asian tiger mosquito to flourish. The insect has spread from its native territory in south-east Asia to Europe in just 20 years.
Professors Lucey and Gostin said it was time for the world to set up a permanent body to monitor new diseases.
“Global health advocates should not have to call for convening an emergency committee for each new international health threat,” they wrote.
“Instead, the WHO should establish a standing emergency committee to meet regularly to advice the director-general whether to declare an emergency, take necessary steps to avert a crisis or both.
“The complexities and apparent increased frequency of emerging infectious disease threats and the catastrophic consequences of delays in the international response, make it no longer tenable to place the sole responsibility and authority with the WHO’s director-general to convene currently ad hoc emergency committees.”
The WHO, which said last month that yellow fever was a threat to the entire world, said that holding an emergency committee meeting on yellow fever was "under discussion".
"The Angola outbreak is of particular concern because of its urban nature and the possibility of international spread," it said, adding that more than 11.6 million doses of the vaccine had been sent to Angola and another 2.2 million doses "on their way" to the Democratic Republic of Congo (DRC).
WHO is also helping Angola and DRC to carry out mass immunisation campaigns in the affected areas, detect new cases, and control mosquitoes and other disease vectors.
It added: "WHO is actively monitoring possibilities of international exportation to other countries and heightening global surveillance to identify newly affected countries."
On its website, WHO warns: "The risk of international spread is greater than before. In the past devastating outbreaks occurred mainly in sea ports. Today, most cities are connected to most of the world by more rapid means of transport, train or plane.
“So far, the virus circulation has remained within the borders of historically endemic countries, but the virus could spread quickly and cause epidemics in areas with a high density of vectors and a non-immune population.”
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