According to the World Health Organization (WHO), the current Ebola outbreak in the DRC’s North Kivu and Ituri provinces has seen 1102 confirmed Ebola infections leading to 675 deaths. It’s the largest outbreak of the virus since the 2014-2016 outbreak in West Africa, which led to 28,616 confirmed cases of Ebola infection and 11,310 reported deaths in Guinea, Liberia, and Sierra Leone. The recent NEJM study details work by investigators from the Partnership for Research on Ebola Virus in Liberia (PREVAIL), who conducted a cohort study known as PREVAIL III. The team followed Ebola infection survivors from the West African outbreak, as well as their close contacts to serve as controls for 12 months.
From June 2015 through June 2017 the study enrolled a total of 966 Ebola antibody-positive survivors of any age and 2350 antibody-negative controls, 90% of whom were followed for 12 months. Investigators examined both survivors and controls at study entry and every 6 months thereafter. This included medical history assessments, physical examinations, blood collection, routine chemical analyses, and detailed eye examinations conducted by an ophthalmologist.
During the course of the study, Ebola infection survivors reported having 6 symptoms significantly more often than controls: urinary frequency (14.7% vs. 3.4%), headache (47.6% vs. 35.6%), fatigue (18.4% vs. 6.3%), muscle pain (23.1% vs. 10.1%), memory loss (29.2% vs. 4.8%), and joint pain (47.5% vs. 17.5%). No new symptoms emerged in the study period.
In an interview with Contagion®, study co-author Cavan Reilly, Phd, discussed the study group’s findings.“We have shown that most symptoms slowly resolve, although there is still a substantial health burden for over a year after resolution of acute symptoms,” said Reilly. The study noted that interaction with health care providers and resolution of tissue damage contributed to the decline in symptoms. “By using a large sample with controls and verification of past infection status with antibody detection we can more faithfully attribute sequelae to past infection.”
In addition, Ebola survivors were more likely than controls to report abnormal abdominal, chest, neurologic, and musculoskeletal findings—which declined during the study period—as well as uveitis, which actually rose in prevalence from 26.4% to 33.3% among survivors during the course of the study. A 12% prevalence of uveitis at baseline among the control group highlighted the importance of including controls and the presence of non-Ebola causes of uveitis. Reilly notes that the study adds to prior findings showing that care from ophthalmologists is critical for many survivors of Ebola virus disease.
PREVAIL III also found that Ebola RNA was detected in 30% of the semen samples collected from 267 antibody-positive male survivors, and for up to 40 months from time of illness. “We have documented that shedding of viral RNA in semen is intermittent and persists for a longer period of time than previously recognized,” explained Reilly. “We are continuing to follow study participants for at least 5 years. Additional observations will be reported in forthcoming publications.”
For the most recent case counts in the Ebola outbreak in the DRC, check out the Contagion® Outbreak Monitor.