Diallo MSK, et al. - Researchers performed this retrospective, cross-sectional observational study recruiting individuals who had been in physical contact with a patient with Ebola virus disease, from four medical centers in Guinea (Conakry, Macenta, N'zérékoré, and Forécariah) to determine the risk factors for seropositivity. In addition, they estimated the prevalence of Ebola virus infection in unvaccinated contact persons. In a study population of 1390 contact persons (median age was 26 years), 216 (16%) contact persons reported symptoms. Eighteen (8·33%) of 216 paucisymptomatic contact persons and 39 (3·32%) of 1174 (2–4) asymptomatic individuals were seropositive. Participation in burial rituals and exposure to blood or vomit were correlated with increased seropositivity. This study presents a new assessment of the prevalence of Ebola virus infection among contact persons according to exposure. Furthermore, evidence was gained for the occurrence of paucisymptomatic cases that emphasizes the significance of closely monitoring at-risk contact persons.