West African Ebola Epidemic after One Year — Slowing but Not Yet under Control

Abstract

During the period from early June to mid-September 2014, the epidemic of Ebola virus disease (EVD) in Guinea, Liberia, and Sierra Leone grew exponentially, with national doubling times of between 16 and 30 days.¹ On the basis of case reports through mid-September, and assuming no change in the trajectory of the epidemic, we predicted a cumulative total of 21,000 cases in these three countries by November 2.¹ In fact, the epidemic did change course in September: the increase in case incidence appears to have halted in Guinea and Sierra Leone and has reversed in Liberia ( Figure 1 ). Now, 1 year after the first case was reported in December 2013,² we report updated epidemiologic findings for the three countries that have been most affected, using data recorded through December 14.