The number of Ebola cases in West Africa could reach 1.4 million by the end of January if trends continue without an immediate and massive scale-up in response, according to a new estimate by the Centers for Disease Control and Prevention.
The report released Tuesday is a tool the agency has developed to help with efforts to slow transmission of the epidemic and estimate the potential number of future cases. Researchers say the total number of cases is vastly underreported by a factor of 2.5 in Sierra Leone and Liberia, two of the three hardest-hit countries. Using this correction factor, researchers estimate that approximately 21,000 total cases will have occurred in Liberia and Sierra Leone by Sept. 30. Reported cases in those two countries are doubling approximately every 20 days, researchers said.
“Extrapolating trends to January 20, 2015, without additional interventions or changes in community behavior,” such as much-improved safe burial practices, the researchers estimate that the number of Ebola cases in Liberia and Sierra Leone could be between approximately 550,000 to 1.4 million.
“The findings in this report underscore the substantial public health challenges posed by the predicted number of future Ebola cases,” the researchers wrote. “If conditions continue without scale-up of interventions, cases will continue to double approximately every 20 days, and the number of cases in West Africa will rapidly reach extraordinary levels.”
They also said their assumptions may not fully account for sick patients who are turned away from treatment centers that don’t have any spare beds. That suggests the number of underreported cases could be even higher.
CDC Director Tom Frieden cautioned that the estimates in the report don’t take into account actions taken or planned since August by the United States and the international community.
“We anticipate that these actions will slow the spread of the epidemic,” he said in a statement. The estimates in the report are based on data from August and “reflect a moment in time before recent significant increases in efforts to improve treatment and isolation.”
He said the tool developed by the CDC to make these projections provides the ability to help Ebola response planners make more informed decisions on the emergency response to help bring the outbreak under control – and what can happen if these resources are not brought to bear quickly.
“It is still possible to reverse the epidemic, and we believe this can be done if a sufficient number of all patients are effectively isolated, either in Ebola Treatment Units or in other settings, such as community-based or home care,” he said. “Once a sufficient number of Ebola patients are isolated, cases will decline very rapidly – almost as rapidly as they rose.”