# Understanding the epidemiology and natural history of unrecognized Ebola virus infection

> **NIH NIH K23** · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · 2021 · $199,098

## Abstract

PROJECT SUMMARY/ABSTRACT
 A large number of Ebola virus infections may have been unrecognized during the 2013-2016 West
African outbreak, both undiagnosed Ebola virus disease (EVD) as well as mildly symptomatic and
asymptomatic infection. The epidemiology and natural history of infection in this unrecognized population,
which is defined by positive Ebola serology and a history of exposure, are poorly understood. For instance, it is
unknown if individuals with unrecognized infection have similar clinical and psychosocial sequelae as
recognized cases, such as uveitis, depression, and work-related disability. Understanding the extent to which
post-infectious sequelae occur and the predictors of unrecognized infection will bolster efforts to screen and
link unrecognized, infected individuals - both symptomatic and asymptomatic - to survivor services and to
better identify this population in future outbreaks.
 I will study a well characterized cohort of individuals with serological evidence of past, unrecognized,
Ebola virus infection. I will utilize an existing cohort of close contacts of EVD survivors developed by the
National Institute of Allergy and Infectious Diseases' Partnership for Research on Ebola Virus in Liberia
(PREVAIL). The PREVAIL program began a natural history study of EVD survivors and their close contacts in
June 2015. Over 1,100 EVD survivors have been enrolled with the aim of characterizing their post-EVD clinical
sequelae, viral persistence, and durability of antibody response. Over 2,300 close contacts have also been
enrolled as the comparison population. A total of 230 (10%) close contacts of EVD survivors were found to be
seropositive by the quantitative FANG Ebola EIA and had not been reported as having had EVD. At study
baseline, 57% of this population reported having had symptoms in the three-week period after exposure to
Ebola virus, and 43% did not. This will be the first systematic, longitudinal study of unrecognized survivors of
Ebola virus infection.
 This K23 proposal aims to: (1) identify the clinical sequelae of unrecognized, symptomatic Ebola virus
infection, (2) identify the predictors and clinical sequelae of unrecognized, asymptomatic Ebola virus infection,
and (3) identify psychosocial sequelae among unrecognized, symptomatic EVD survivors. My career
development aims involve: (1) design of observational studies, (2) advanced biostatistics, and (3) field
epidemiology in low-resource settings. This plan will be carried out with coursework, directed study, and the
guidance of an international team of mentors. In addition to future study of longer-term sequelae of EVD, I will
apply these skills and expertise to an R01 application in which I study the epidemiology and natural history of
other viral hemorrhagic fever and emerging infectious diseases such as Marburg virus and monkeypox.

## Key facts

- **NIH application ID:** 10224704
- **Project number:** 5K23AI146268-03
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
- **Principal Investigator:** John Daniel Kelly
- **Activity code:** K23 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $199,098
- **Award type:** 5
- **Project period:** 2019-08-01 → 2023-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10224704

## Citation

> US National Institutes of Health, RePORTER application 10224704, Understanding the epidemiology and natural history of unrecognized Ebola virus infection (5K23AI146268-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10224704. Licensed CC0.

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