Preliminary findings from PREVAIL III, a study of Ebola virus disease (EVD) survivors being conducted in Liberia, indicate that both Ebola survivors and their close contacts have a high burden of illness. However, the prevalence of eye, musculoskeletal, and neurological complications was greater among the individuals who survived EVD.
Initial results from PREVAIL III were presented this evening at the Conference on Retroviruses and Opportunistic Infections in Boston by study co-principal investigator Mosoka Fallah, Ph.D., M.P.H., with the Liberian Ministry of Health. PREVAIL III began in June 2015 and is co-sponsored by the Liberian Ministry of Health and the National Institute of Allergy and Infectious Diseases (NIAID), part of the NIH. The trial is expected to enroll 7,500 people throughout Liberia, including 1,500 EVD survivors of any age and up to 6,000 of their close contacts, with participants followed for up to five years and study visits every six months.
Through February 15, 2016, the study had enrolled 1,049 EVD survivors and 1,034 close contacts with average ages of 30 and 26 years, respectively. On average, survivors enrolled in the study about one year after experiencing EVD symptoms. Investigators found that as self-reported by survivors, 60 percent experienced eye problems, 53 percent had musculoskeletal problems and 68 percent had neurological difficulties. Close contacts, who were potentially exposed to the Ebola virus but did not become infected, reported similar problems, albeit less frequently: 59 percent reported vision problems, 28 percent had musculoskeletal issues, and 48 percent had neurological issues.
Ninety-seven male survivors provided one or more semen samples for analysis. Overall, 38 percent of these men had Ebola detected in their semen at least once. In one-third of the 69 men who were tested more than once, virus detection in semen was intermittent (negative results then positive, or vice versa). The maximum amount of time between EVD symptoms and detection of Ebola in a semen sample was 18 months. Most survivors reported being sexually active. In a subset of 126 close contacts who reported sexual activity with a survivor, only four percent reported regular condom use, raising concerns about the potential for sexual transmission of EVD. However, so far, no cases of sexual transmission of Ebola have been detected in the PREVAIL III study.
These findings were presented today at the 23rd Conference on Retroviruses and Opportunistic Infections at the John B. Hynes Veterans Memorial Convention Center in Boston.
NIAID Director Anthony S. Fauci, M.D., and Michael C. Sneller, M.D., from NIAID’s Laboratory of Immunoregulation and co-investigator of the PREVAIL III study, are available for comment.