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. 2016 Aug;22(8):1403-11.
doi: 10.3201/eid2208.160163. Epub 2016 Aug 15.

Exposure-Specific and Age-Specific Attack Rates for Ebola Virus Disease in Ebola-Affected Households, Sierra Leone

Hilary Bower, Sembia Johnson, Mohamed S Bangura, Alie Joshua Kamara, Osman Kamara, Saidu H Mansaray, Daniel Sesay, Cecilia Turay, Francesco Checchi, Judith R Glynn

Exposure-Specific and Age-Specific Attack Rates for Ebola Virus Disease in Ebola-Affected Households, Sierra Leone

Hilary Bower et al. Emerg Infect Dis. 2016 Aug.

Abstract

Using histories of household members of Ebola virus disease (EVD) survivors in Sierra Leone, we calculated risk of EVD by age and exposure level, adjusting for confounding and clustering, and estimated relative risks. Of 937 household members in 94 households, 448 (48%) had had EVD. Highly correlated with exposure, EVD risk ranged from 83% for touching a corpse to 8% for minimal contact and varied by age group: 43% for children <2 years of age; 30% for those 5-14 years of age; and >60% for adults >30 years of age. Compared with risk for persons 20-29 years of age, exposure-adjusted relative risks were lower for those 5-9 (0.70), 10-14 (0.64), and 15-19 (0.71) years of age but not for children <2 (0.92) or 2-4 (0.97) years of age. Lower risk for 5-19-year-olds, after adjustment for exposure, suggests decreased susceptibility in this group.

Keywords: Ebola; Ebola virus; Ebola virus disease; Sierra Leone; attack rates; cohort study; exposures; households; infectious disease transmission; risk factors; survivors; transmission; viruses.

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Figures

Figure 1
Figure 1
Flow diagram showing the population composition for study of Ebola-affected households related to survivors from the Kerry Town Ebola Treatment Centre (ETC), Sierra Leone, 2014–2015. EVD, Ebola virus disease. *Includes 23 not present for interview. †Includes 1 who died after discharge. ‡Includes 5 not present for interview.
Figure 2
Figure 2
Risk for Ebola virus disease in Ebola-affected households of Kerry Town Ebola Treatment Centre survivors, by age and sex, Sierra Leone, 2014–2015. A) Risk by age group; bars indicate 95% CIs. B) Risk by sex and age group with and without probable cases.
Figure 3
Figure 3
Levels of exposure to Ebola virus disease among households of Kerry Town survivors, excluding primary case-patients, by age and sex, Sierra Leone, 2014–2015. A) Male participants; B) female participants. Levels of exposure correspond to those shown in Table 1. Min–none, minimum or no exposure.
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References

    1. Dowell SF. Ebola hemorrhagic fever: why were children spared? Pediatr Infect Dis J. 1996;15:189–91. 10.1097/00006454-199603000-00002 - DOI - PubMed
    1. Rosello A, Mossoko M, Flasche S, Van Hoek AJ, Mbala P, Camacho A, et al. Ebola virus disease in the Democratic Republic of the Congo, 1976–2014. eLife. 2015;4: e09015. 10.7554/eLife.09015 - DOI - PMC - PubMed
    1. Ebola hemorrhagic fever in Zaire, 1976. Bull World Health Organ. 1978;56:271–93. - PMC - PubMed
    1. World Health Organization Ebola Response Team; Agua-Agum J, Ariyarajah A, Blake IM, Cori A, Donnelly CA, Dorigatti I, et al.. Ebola virus disease among children in West Africa. N Engl J Med. 2015;372:1274–7. 10.1056/NEJMc1415318 - DOI - PMC - PubMed
    1. World Health Organization Ebola Response Team; Agua-Agum J, Ariyarajah A, Aylward B, Blake IM, Brennan R, Cori A, et al. West African Ebola epidemic after one year—slowing but not yet under control. N Engl J Med. 2015;372:584–7. 10.1056/NEJMc1414992 - DOI - PMC - PubMed