Diallo M. S. K. auteur aut IRD Rabilloud M. auteur aut IRD Ayouba Ahidjo auteur aut IRD Toure A. auteur aut IRD Thaurignac Guillaume auteur aut IRD Keita A.K. auteur aut IRD Butel Christelle auteur aut IRD Kpamou C. auteur aut IRD Barry T. A. auteur aut IRD Sall M. D. auteur aut IRD Camara I. auteur aut IRD Leroy S. auteur aut IRD Msellati Philippe auteur aut IRD Ecochard R. auteur aut IRD Peeters Martine auteur aut IRD Sow M. S. auteur aut IRD Delaporte E. auteur aut IRD Etard Jean-François auteur aut IRD Taverne Bernard collab. clb IRD Contactebogui Study Group auteur aut IRD text journalArticle eng text/pdf born digital access Background The prevalence of Ebola virus infection among people who have been in contact with patients with Ebola virus disease remains unclear, but is essential to understand the dynamics of transmission. This study aimed to identify risk factors for seropositivity and to estimate the prevalence of Ebola virus infection in unvaccinated contact persons. Methods In this retrospective, cross-sectional observational study, we recruited individuals between May 12, 2016, and Sept 8, 2017, who had been in physical contact with a patient with Ebola virus disease, from four medical centres in Guinea (Conakry, Macenta, N'zerekore, and Forecariah). Contact persons had to be 7 years or older and not diagnosed with Ebola virus disease. Participants were selected through the Postebogui survivors' cohort. We collected self-reported information on exposure and occurrence of symptoms after exposure using a questionnaire, and tested antibody response against glycoprotein, nucleoprotein, and 40-kDa viral protein of Zaire Ebola virus by taking a blood sample. The prevalence of Ebola virus infection was estimated with a latent class model. Findings 1721 contact persons were interviewed and given blood tests, 331 of whom reported a history of vaccination so were excluded, resulting in a study population of 1390. Symptoms were reported by 216 (16%) contact persons. The median age of participants was 26 years (range 7-88) and 682 (49%) were male. Seropositivity was identified in 18 (8.33%, 95% CI 5.01-12.80) of 216 paucisymptomatic contact persons and 39 (3.32%, 5.01-12.80) of 1174 (2-4) asymptomatic individuals (p=0.0021). Seropositivity increased with participation in burial rituals (adjusted odds ratio [aOR] 2.30, 95% CI 1.21-4.17; p=0.0079) and exposure to blood or vomit (aOR 2.15, 1.23-3.91; p=0.0090). Frequency of Ebola virus infection varied from 3.06% (95% CI 1.84-5.05) in asymptomatic contact persons who did not participate in burial rituals to 5.98% (2.81-8.18) in those who did, and from 7.17% (3.94-9.09) in paucisymptomatic contact persons who did not participate in burial rituals to 17.16% (12.42-22.31) among those who did. Interpretation This study provides a new assessment of the prevalence of Ebola virus infection among contact persons according to exposure, provides evidence for the occurrence of paucisymptomatic cases, and reinforces the importance of closely monitoring at-risk contact persons. specialized GUINEE 052 050 19 3 308-316 2019 1473-3099 https://www.documentation.ird.fr/hor/fdi:010075278 10.1016/s1473-3099(18)30649-2 1473-3099 [F B010075278] https://www.documentation.ird.fr/hor/fdi:010075278 https://www.documentation.ird.fr/intranet/publi/2019/03/010075278.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2019-04-03 2025-02-24 fdi:010075278 fre