META-ANALYSI ON THE RISK OF MORTALITY IN PERSON WITH EBOLA VIRUS DISEASE. (1976-2014)

The Ebola virus disease outbreak that started in western Africa in 2013 was unprecedented because it spread within densely populated urban environment and affected thousands of people. As a result, previous advice and guidelines need to be critically received, especially with regard to transmission risk in different contexts. A total of 20 reports were selected from 634 found in the initial search. Data were extracted from eligible articles and summarized narratively with partial Meta-Analysis. Eight papers gave numerical odds for contracting filovirus illness; 67 further articles provided supporting anecdotal observations about how transmission probably occurred for individuals. Many forms of contact (conversation, sharing a meal, sharing a bed, direct or indirect touching) were unlikely to result in disease transmission during incubation or early illness. Among household contacts who reported directly touching a case, the attack rate was 23% [95% confidence interval (CI) 26-38%]. Risk of disease transmission between household members without direct contact was low (1%; 95% CI 0-5%). Caring for a case in the community, especially until death, and participation in traditional funeral rites were strongly associated with acquiring disease, probably due to a high degree of direct physical contact with case or cadaver. Transmission of filovirus in unlikely except through close contact, especially during the most severe stages of acute illness. More data were needed about the context, intimacy and timing of contact required to raise the odds of disease transmission. Risk of factors specific to urban settings may need to be determined