Surviving Ebola: A historical cohort study of Ebola mortality and survival in Sierra Leone 2014-2015

PLoS One. 2018 Dec 27;13(12):e0209655. doi: 10.1371/journal.pone.0209655. eCollection 2018.

Abstract

Background: While a number of predictors for Ebola mortality have been identified, less is known about post-viral symptoms. The identification of acute-illness predictors for post-viral symptoms could allow the selection of patients for more active follow up in the future, and those in whom early interventions may be beneficial in the long term. Studying predictors of both mortality and post-viral symptoms within a single cohort of patients could also further our understanding of the pathophysiology of survivor sequelae.

Methods/principal findings: We performed a historical cohort study using data collected as part of routine clinical care from an Ebola Treatment Centre (ETC) in Kerry Town, Sierra Leone, in order to identify predictors of mortality and of post-viral symptoms. Variables included as potential predictors were sex, age, date of admission, first recorded viral load at the ETC and symptoms (recorded upon presentation at the ETC). Multivariable logistic regression was used to identify predictors. Of 263 Ebola-confirmed patients admitted between November 2014 and March 2015, 151 (57%) survived to ETC discharge. Viral load was the strongest predictor of mortality (adjusted OR comparing high with low viral load: 84.97, 95% CI 30.87-345.94). We did not find evidence that a high viral load predicted post-viral symptoms (ocular: 1.17, 95% CI 0.35-3.97; musculoskeletal: 1.07, 95% CI 0.28-4.08). Ocular post-viral symptoms were more common in females (2.31, 95% CI 0.98-5.43) and in those who had experienced hiccups during the acute phase (4.73, 95% CI 0.90-24.73).

Conclusions/significance: These findings may add epidemiological support to the hypothesis that post-viral symptoms have an immune-mediated aspect and may not only be a consequence of high viral load and disease severity.

Publication types

  • Historical Article
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Cohort Studies
  • Disease Outbreaks
  • Ebolavirus*
  • Female
  • Hemorrhagic Fever, Ebola / epidemiology
  • Hemorrhagic Fever, Ebola / history
  • Hemorrhagic Fever, Ebola / mortality*
  • History, 21st Century
  • Humans
  • Male
  • Mortality
  • Population Surveillance
  • Risk Factors
  • Sierra Leone / epidemiology
  • Survivors
  • Viral Load
  • Young Adult

Grants and funding

This work was supported by Save the Children’s Ebola Emergency Public Appeal. The Public Health England EVD laboratory operation was funded through the UK Government Department for International Development. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.