Between 550,000 and 1.4 million people in West Africa could be infected with the Ebola virus by January 20, 2015, according to a study published yesterday by researchers at the US Centers for Disease Control and Prevention (CDC).
The top range of the estimate, 1.4 million, assumes that the number of cases – 5,864 according to the count kept by the World Health Organisation (WHO) – is significantly underreported, and that it is likely that 2.5 times as many cases, or about 15,000, have in fact occurred.
CDC emphasised that the projections, based on an epidemiological model that takes into account how many people each Ebola patient eventually infects as well as other factors, are based on data from late August.
Therefore, they do not account for the recently announced US government Ebola relief effort, which includes sending 3,000 members of the armed forces to the stricken region and training 500 healthcare workers per week.
“Extensive, immediate actions – such as those already started – can bring the epidemic to a tipping point to start a rapid decline in cases,” CDC said in a statement.
“A surge now can break the back of the epidemic,” CDC director Dr Thomas Frieden told reporters. “If you get enough people effectively isolated, the epidemic can be stopped.
“I am confident the most dire projections will not come to pass,” he added, now that the international community has begun to respond.
Also yesterday, WHO experts projected that Ebola outbreak could infect 20,000 people as soon as early November unless rigorous infection control measures are implemented, and might become a constant, endemic disease in the region rather than being completely eradicated.
If you get enough people effectively isolated, the epidemic can be stopped
In contrast, the WHO in late August predicted that the virus could strike 20,000 people by the middle of 2015. The current death toll is at least 2,811 out of the reported 5,864 cases, the UN agency said.
According to the CDC analysis, published in the journal Morbidity and Mortality Weekly Report, reported cases in Liberia are doubling every 15 to 20 days, while those in Sierra Leone are doubling every 30 to 40 days.
The essence of the CDC analysis is a mathematical model, called EbolaResponse, which allows researchers to see how different actions affect the course of the epidemic.
For instance, it shows that if by late December 70 per cent of Ebola patients have received treatment – or safe burial, if medical efforts fail – thereby slashing transmission rates, the epidemic begins to decrease and eventually end by late January 2015. The Excel 2010-based model is available at http://stacks.cdc.gov/view/cdc/24900 .
Experimental drugs including compounds from Mapp Biopharmaceutical, Sarepta and Tekmira will be tested in affected West African states for the first time in a bid to fast-track trials, the Wellcome Trust said yesterday. Announcing a £3.2 million grant, the charity said it would “enable multiple partners around the world to quickly establish clinical trials at existing centres”.
On the same day, Sierra Leone’s army “sealed off' the borders with Liberia and Guinea in a bid to halt the spread of the virus, a spokesman said.
Ebola has killed more than 2,800 people in the three countries since the outbreak began in Guinea earlier this year.