Persistence of Ebola virus in semen among Ebola virus disease survivors in Sierra Leone: A cohort study of frequency, duration, and risk factors

Author summary Why was this study done? Evidence of traces of Ebola virus in semen had been reported among survivors for a very long time after their disease. This study originated out of a need to expand understanding beyond single reported cases, to gain knowledge on how many male survivors have Ebola virus persistence in semen over time, and for how long on average. We also aimed to analyze factors associated with longer persistence that could provide information on hypotheses on why some men carry virus in their semen for a very long time after the acute disease. What did the researchers do and find? In this study, 220 men who had survived Ebola disease in Sierra Leone during 2015-2016 provided semen specimens, and all of those who had traces of Ebola virus detected were followed every other week until their specimen turned negative. Seventy-five percent of these men still had traces of Ebola virus in their semen specimen at 6 months after being discharged following acute EVD, and 50% at 204 days. We also found that longer persistence of virus was significantly associated with severe acute EVD and older age. What do these findings mean? We show there is an urgent need to organize a national semen testing program as part of Ebola epidemic preparedness and response. The findings also show that in addition to testing, targeted safe sex counseling and free access to condoms should be a priority from the start of an outbreak. While we show that most of the survivors had traces of virus in semen at 6 months, more research is needed to understand the impact of viral RNA in semen on transmission of Ebola virus. Background Sexual transmission chains of Ebola virus (EBOV) have been verified and linked to EBOV RNA persistence in semen, post-recovery. The rate of semen persistence over time, including the average duration of persistence among Ebola virus disease (EVD) survivors, is not well known. This cohort study aimed to analyze population estimates of EBOV RNA persistence rates in semen over time, and associated risk factors in a population of survivors from Sierra Leone. Methods and findings In this cohort study from May 2015 to April 2017 in Sierra Leone, recruitment was conducted in 2 phases; the first enrolled 100 male participants from the Western Area District in the capital of Freetown, and the second enrolled 120 men from the Western Area District and from Lungi, Port Loko District. Mean age of participants was 31 years. The men provided semen for test