The deadly Ebola epidemic in Liberia could likely be eliminated by June if the current high rate of hospitalisation and vigilance can be maintained, according to a new model developed by scientists.
The model, developed by researchers at the University of Georgia (UGA) and Pennsylvania State University, includes such factors as the location of infection and treatment, the development of hospital capacity and the adoption of safe burial practices and is probably the first to include all those elements. The model projected that, if an 85 per cent hospitalisation rate can be achieved, the Ebola epidemic in Liberia should be largely contained by June 2015.
“That’s a realistic possibility but not a foregone conclusion. What’s needed is to maintain the current level of vigilance and keep pressing forward as hard as we can,” said John Drake, an associate professor in the UGA Odum School of Ecology who led the study published in the journal PLOS Biology. In the study, researchers used a mathematical formulation known as branching processes - a method for keeping track of all possible epidemic outcomes in proportion to their probabilities - calibrated with newly developed methods.
Drake and his colleagues started with information gleaned from earlier Ebola outbreaks. They included data about variables such as the numbers of patients hospitalised health care workers infected, which allowed them to estimate the level of under-reporting; rates of transmission in hospitals, the community and from funerals; and the effectiveness of infection control measures.
Once they had a working model with plausible parameters, they fine-tuned it using data from the World Health Organisation and the Liberia Ministry of Health for the period from July 4 through September 2, 2014. This included information about new cases as well as changes in behaviour and public health interventions during that time, such as the addition of roughly 300 hospital beds and the adoption of safer burial practices.
Liberia continued to add hospital beds after September 2, so in mid-December, Drake and his team updated the model to include information collected through December 1. Using reported data rather than estimates from the earlier version of the model significantly cut down on the range of future possibilities, showing that the response by the Liberian government and international groups had greatly reduced the likelihood of a massive epidemic.
Ebola virus has killed more than 7,800 people, almost all in West Africa, since it broke out a year ago. Sierra Leone, which has overtaken Liberia as the country with the most infections, counted 9,446 cases and 2,758 deaths on December 28.
Liberia has seen a clear decrease in transmission over the past month. As of December 28, the country had recorded 8,018 cases and 3,423 deaths. PTI
