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

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 testing, analyzed by quantitative reverse transcription PCR (qRT-PCR) for the presence of EBOV RNA. Follow-up occurred every 2 weeks until the endpoint, defined as 2 consecutive negative qRT-PCR results of semen specimen testing for EBOV RNA. Participants were matched with the Sierra Leone EVD case database to retrieve cycle threshold (Ct) values from the qRT-PCR analysis done in blood during acute disease. A purposive sampling strategy was used, and the included sample composition was compared to the national EVD survivor database to understand deviations from the general male survivor population. At 180 days (6 months) after Ebola treatment unit (ETU) discharge, the EBOV RNA semen positive rate was 75.4% (95% CI 66.9%-82.0%). The median persistence duration was 204 days, with 50% of men having cleared their semen of EBOV RNA after this time. At 270 days, persistence was 26.8% (95% CI 20.0%-34.2%), and at 360 days, 6.0% (95% CI 3.1%-10.2%). Longer persistence was significantly associated with severe acute disease, with probability of persistence in this population at 1 year at 10.1% (95% CI 4.6%-19.8%) compared to the probability approaching 0% for those with mild acute disease. Age showed a dose-response pattern, where the youngest men (≤25 years) were 3.17 (95% CI 1.60, 6.29) times more likely to be EBOV RNA negative in semen, and men aged 26-35 years were 1.85 (95% CI 1.04, 3.28) times more likely to be negative, than men aged >35 years. Among participants with both severe acute EVD and a higher age (>35 years), persistence remained above 20% (95% CI 6.0%-50.6%) at 1 year. Uptake of safe sex recommendations 3 months after ETU discharge was low among a third of survivors. The sample was largely representative of male survivors in Sierra Leone. A limitation of this study is the lack of knowledge about infectiousness. CONCLUSIONS: In this study we observed that EBOV RNA persistence in semen was a frequent phenomenon, with high population rates over time. This finding will inform forthcoming updated recommendations on risk reduction strategies relating to sexual transmission of EBOV. Our findings support implementation of a semen testing program as part of epidemic preparedness and response. Further, the results will enable planning of the magnitude of testing and targeted counseling needs over time.

Excess mortality and tuberculosis among individuals with prolonged cough: a population-based study from Vietnam.

SETTING: A demographic surveillance site in north-west Vietnam. OBJECTIVES: To compare notification rates of sputum smear-positive tuberculosis (TB) and mortality rates between the general population and individuals with prolonged cough. DESIGN: A cohort study of 559 prolonged cough cases in a total population of 35,832, observed over 2.5 years. Outcome measures were sputum smear-positive TB and death. RESULTS: The age-standardised smear-positive TB notification rate among cough cases (553/100,000 person-years [py], 95%CI 268-1143) was significantly higher than in the general population (50/100,000 py, 95%CI 43-57), with a relative risk of 11.06 (95%CI 8.28-14.77). Among those who had a chest X-ray suggestive of TB but negative sputum smears prior to the study start, the rate was 6542/100,000 py (95%CI 2906-12,511). The cough cohort had a 2.61 (95%CI 2.38-2.87) times higher risk of dying than the general population. CONCLUSIONS: Individuals with prolonged cough in this study run a significantly increased risk of developing infectious TB and of dying. We recommend further evaluations of improved follow-up systems aimed at identifying and treating sputum smear-negative TB cases before they convert to an infectious stage.

An economic analysis of persons with prolonged cough in rural northern Vietnam.

SETTING: Epidemiological surveillance in the Bavi district, northern Vietnam. OBJECTIVE: To compare the prevalences of prolonged cough across socio-economic groups defined by income, expenditure and official classification. To investigate inequalities using the Illness Concentration Index. DESIGN: Interviews in 11,547 randomly selected households with 35,832 persons aged 15 years or more. Prolonged cough was identified in 559 persons (1.5%). RESULTS: Differences between cough prevalences were found for all socio-economic indicators, but were less clear for expenditure. Lower economic groups reported higher prevalences than higher groups, and prevalences were higher among the elderly. Male was similar to female prevalence. The illness gap between the poor and rich was wider for men. The Illness Concentration Index confirmed these findings. CONCLUSION: Inequalities were found when using both different socio-economic indicators and different analysis approaches.

Knowledge about tuberculosis and its treatment among new pulmonary TB patients in the north and central regions of Vietnam.

SETTING: Tuberculosis (TB) units in 42 districts in north and central Vietnam were included in the study. OBJECTIVES: To describe patients' knowledge of TB and to evaluate the impact of the National Tuberculosis Programme's health education. DESIGN: New pulmonary TB patients who had received TB treatment for a minimum of 1 month were interviewed using a structured questionnaire. RESULTS: A total of 364 patients were interviewed; 93% of respondents reported receiving TB information from the health staff. Apart from health education, many patients reported TB information from the TV. This was more common among men than women (71.4% vs. 51.3%). The average knowledge score was 7.07 +/- 2.02 (maxium 10). This was significantly associated with level of education and receiving health education. More than half of the patients expressed fear of being known as TB patients in the community. CONCLUSIONS: Knowledge about TB and its treatment was generally high. Marginalised groups with limited access to media and low education levels may benefit from specially targeted educational interventions. To reduce stigma and the impact of social consequences of TB, an ongoing health education programme designed to increase the knowledge level in the whole population appears warranted.