Published: 15-10-2015 10:49 | Updated: 01-12-2015 13:24

Ebola virus can persist in the semen of survivors

Preliminary results of a study into persistence of Ebola virus in body fluids show that some men still produce semen samples that test positive for Ebola virus nine months after onset of symptoms.

The first phase of this study has focused on testing for Ebola virus in semen because of past research showing persistence in that body fluid. Better understanding of viral persistence in semen is important for supporting survivors to recover and to move forward with their lives.

Ninety three men over the age of 18 from Freetown, Sierra Leone, provided a semen sample that was tested to detect the presence of Ebola virus genetic material. The men enrolled in the study between two and 10 months after their illness began. For men who were tested in the first three months after their illness began, all were positive. More than half of men who were tested between four to six months after their illness began were positive, while one quarter of those tested between seven to nine months after their illness began also tested positive. The men were given their test results along with counseling and condoms.

Why some study participants had cleared the fragments of Ebola virus from semen earlier than others remains unclear. Until more is known, the more than 8000 male Ebola survivors across the three countries need appropriate education, counseling and regular testing so they know whether Ebola virus persists in their semen; and the measures they should take to prevent potential exposure of their partners to the virus.

In the current West African outbreak, continued vigilance to identify, provide care for, contain and stop new cases, are key strategies on the road to achieving zero cases.

The report, published in the New England Journal of Medicine, provides the first results of a long-term study being jointly conducted by the Sierra Leone Ministry of Health and Sanitation, Sierra Leone Ministry of Defence, the World Health Organization and the U.S. Centers for Disease Control and Prevention. Professor Anna Ekéus Thorson, Department of Public Health Sciences at Karolinska Institutet is one of the researchers behind the study.


Ebola RNA Persistence in Semen of Ebola Virus Disease Survivors - Preliminary Report”, New England Journal of Medicine, online 14 October 2015, DOI: 10.1056/NEJMoa1511410.

View the press release from the WHO