Community-based assessment of mpox seroprevalence and undocumented exposures in Manitoba and Alberta, Canada
- 1University of Manitoba
Abstract
During the 2022 global mpox outbreak, gay, bisexual and other men who have sex with men (gbMSM) were disproportionately affected. However, the true number of cases is likely higher than reported due in part to the stigma associated with mpox. This stigma may have played an even more influential role on health-seeking behaviour in politically conservative regions, such as the Canadian Prairies. The shifting epidemiology may have also led to misdiagnoses during initial months of the outbreaks. Seroprevalence studies can help assess these gaps in surveillance and population-level immunity. To address this, we conducted a cross-sectional seroprevalence study among 275 individuals who identified as potentially eligible to receive the mpox vaccine in the Canadian provinces of Manitoba and Alberta from June 2024 to December 2025 based on provincial vaccination criteria. This eligibility included, but was not exclusively limited to, gbMSM, gender diverse individuals, and sex workers. Dried blood spots were analyzed using the Meso Scale Discovery Orthopoxvirus assay targeting five orthologous mpox virus and vaccinia virus antigens. In total, 14.5% of individuals self-reported receiving the mpox vaccine and of those without reported Orthopoxvirus vaccination, 5.9% were seroreactive to multiple mpox virus antigens. These results suggest the potential for undetected mpox circulation within Manitoba and Alberta. While primarily men who have sex with men were eligible for the mpox vaccine, an expansive range of gender and sexual orientation identities were classified as seroreactive, suggesting a misalignment between those who were seroreactive and vaccine eligibility criteria. This emphasizes how broader mpox vaccine eligibility, not restricted by specific gender and sexuality requirements, may better encompass those at risk of infection.
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BibTeX
@misc{gork2026communitybased,
title = {{Community-based assessment of mpox seroprevalence and undocumented exposures in Manitoba and Alberta, Canada}},
author = {E. Gork and M. Hunter and N. Battle and N. Wilson and S. Polege and C. Robles and V. Vincent and G. Meyer and H. L. Wallace and L. Saxinger and J. Bullard and M. L. Halbrook and S. Merritt and N. A. Hoff and R. S. Noyce and D. C. Vinh and R. Souleymanov and S. Y. Shaw and P. Mbala-Kingebeni and A. W. Rimoin and V. Meier-Stephenson and J. Kindrachuk},
howpublished = {medRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.17.26363367},
url = {https://www.medrxiv.org/content/10.64898/2026.09.17.26363367v1},
note = {CC BY-ND},
}
RIS
TY - UNPB
TI - Community-based assessment of mpox seroprevalence and undocumented exposures in Manitoba and Alberta, Canada
AU - E. Gork
AU - M. Hunter
AU - N. Battle
AU - N. Wilson
AU - S. Polege
AU - C. Robles
AU - V. Vincent
AU - G. Meyer
AU - H. L. Wallace
AU - L. Saxinger
AU - J. Bullard
AU - M. L. Halbrook
AU - S. Merritt
AU - N. A. Hoff
AU - R. S. Noyce
AU - D. C. Vinh
AU - R. Souleymanov
AU - S. Y. Shaw
AU - P. Mbala-Kingebeni
AU - A. W. Rimoin
AU - V. Meier-Stephenson
AU - J. Kindrachuk
PY - 2026
DA - 2026/09/17
PB - medRxiv
DO - 10.64898/2026.09.17.26363367
UR - https://www.medrxiv.org/content/10.64898/2026.09.17.26363367v1
AB - During the 2022 global mpox outbreak, gay, bisexual and other men who have sex with men (gbMSM) were disproportionately affected. However, the true number of cases is likely higher than reported due in part to the stigma associated with mpox. This stigma may have played an even more influential role on health-seeking behaviour in politically conservative regions, such as the Canadian Prairies. The shifting epidemiology may have also led to misdiagnoses during initial months of the outbreaks. Seroprevalence studies can help assess these gaps in surveillance and population-level immunity. To address this, we conducted a cross-sectional seroprevalence study among 275 individuals who identified as potentially eligible to receive the mpox vaccine in the Canadian provinces of Manitoba and Alberta from June 2024 to December 2025 based on provincial vaccination criteria. This eligibility included, but was not exclusively limited to, gbMSM, gender diverse individuals, and sex workers. Dried blood spots were analyzed using the Meso Scale Discovery Orthopoxvirus assay targeting five orthologous mpox virus and vaccinia virus antigens. In total, 14.5% of individuals self-reported receiving the mpox vaccine and of those without reported Orthopoxvirus vaccination, 5.9% were seroreactive to multiple mpox virus antigens. These results suggest the potential for undetected mpox circulation within Manitoba and Alberta. While primarily men who have sex with men were eligible for the mpox vaccine, an expansive range of gender and sexual orientation identities were classified as seroreactive, suggesting a misalignment between those who were seroreactive and vaccine eligibility criteria. This emphasizes how broader mpox vaccine eligibility, not restricted by specific gender and sexuality requirements, may better encompass those at risk of infection.
ER -