Ebola virus transmission among healthcare workers: genomic epidemiological analysis of the 2014 Kenema Government Hospital outbreak
Abstract
Background: During the 2014 Ebola outbreak in Sierra Leone, widespread infections among healthcare workers at Kenema Government Hospital severely disrupted clinical operations. Whether these infections primarily arose from repeated patient exposures or from transmission among colleagues remained unclear, particularly as patient admissions exceeded the hospital's capacity for safe isolation and care. Methods: We revisited the outbreak using expanded viral surveillance and classical genomic analysis, Bayesian transmission inference with juniper, and firsthand epidemiologic accounts from hospital staff. We analyzed 279 Ebola virus genomes from Kenema District, including 35 from infected healthcare workers, and 514 genomes in the broader transmission reconstruction, explicitly accounting for unsampled cases. Results: The 35 healthcare worker genomes comprised 28 haplotypes, including five shared by multiple cases. In the reconstructed transmission network, 22 candidate healthcare worker-to-healthcare worker links exceeded a posterior probability threshold of 5%, representing 6.1-fold enrichment over expectation. Healthcare workers accounted for 33.2% of expected onward transmissions at their peak in the two-week window beginning June 23, 2014. Firsthand anecdotal accounts situated inferred relationships within specific wards, clinical procedures, and working relationships of KGH, including care of infected colleagues and infections among laboratory, pharmacy, and other personnel beyond routine bedside care. Conclusions: Ebola transmission involved interconnected groups of healthcare workers across multiple hospital departments during a period of severe resource constraints and expanding patient demand. These findings underscore the importance of protecting and surveilling healthcare workers as an interconnected workforce during emerging outbreaks.
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BibTeX
@misc{shin2026ebola,
title = {{Ebola virus transmission among healthcare workers: genomic epidemiological analysis of the 2014 Kenema Government Hospital outbreak}},
author = {Christopher Y. Shin and Mambu Momoh and Christopher Tomkins-Tinch and Augustine Goba and Lansana Kanneh and Foday Alhassan and Michael Gbakie and Mohamed Alex Vandi and Ivan Specht and Patrick Varilly and John S. Schieffelin and Shirlee Wohl and Danny Park and Kristian G. Andersen and Donald Grant and Robert F. Garry and Kayla Barnes and Pardis C. Sabeti},
howpublished = {medRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.26.26366557},
url = {https://www.medrxiv.org/content/10.64898/2026.10.26.26366557v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Ebola virus transmission among healthcare workers: genomic epidemiological analysis of the 2014 Kenema Government Hospital outbreak
AU - Christopher Y. Shin
AU - Mambu Momoh
AU - Christopher Tomkins-Tinch
AU - Augustine Goba
AU - Lansana Kanneh
AU - Foday Alhassan
AU - Michael Gbakie
AU - Mohamed Alex Vandi
AU - Ivan Specht
AU - Patrick Varilly
AU - John S. Schieffelin
AU - Shirlee Wohl
AU - Danny Park
AU - Kristian G. Andersen
AU - Donald Grant
AU - Robert F. Garry
AU - Kayla Barnes
AU - Pardis C. Sabeti
PY - 2026
DA - 2026/10/26
PB - medRxiv
DO - 10.64898/2026.10.26.26366557
UR - https://www.medrxiv.org/content/10.64898/2026.10.26.26366557v1
AB - Background: During the 2014 Ebola outbreak in Sierra Leone, widespread infections among healthcare workers at Kenema Government Hospital severely disrupted clinical operations. Whether these infections primarily arose from repeated patient exposures or from transmission among colleagues remained unclear, particularly as patient admissions exceeded the hospital's capacity for safe isolation and care. Methods: We revisited the outbreak using expanded viral surveillance and classical genomic analysis, Bayesian transmission inference with juniper, and firsthand epidemiologic accounts from hospital staff. We analyzed 279 Ebola virus genomes from Kenema District, including 35 from infected healthcare workers, and 514 genomes in the broader transmission reconstruction, explicitly accounting for unsampled cases. Results: The 35 healthcare worker genomes comprised 28 haplotypes, including five shared by multiple cases. In the reconstructed transmission network, 22 candidate healthcare worker-to-healthcare worker links exceeded a posterior probability threshold of 5%, representing 6.1-fold enrichment over expectation. Healthcare workers accounted for 33.2% of expected onward transmissions at their peak in the two-week window beginning June 23, 2014. Firsthand anecdotal accounts situated inferred relationships within specific wards, clinical procedures, and working relationships of KGH, including care of infected colleagues and infections among laboratory, pharmacy, and other personnel beyond routine bedside care. Conclusions: Ebola transmission involved interconnected groups of healthcare workers across multiple hospital departments during a period of severe resource constraints and expanding patient demand. These findings underscore the importance of protecting and surveilling healthcare workers as an interconnected workforce during emerging outbreaks.
ER -