A peer-educator driven approach for sampling populations at increase mpox risk in the Democratic Republic of the Congo: Implications for surveillance and response

Authors: MERRITT, SYDNEY - University Of California (UCLA); HALBROOK, MEGAN - University Of California (UCLA); ANTA, YVON - Institute National Research Biomedical; MUKADI, PATRICK - Institute National Research Biomedical; HASIVIRWE VAKANIAKI, EMMANUEL - Institute National Research Biomedical; MUKADI, DANIEL - Institute National Research Biomedical; LUNYANGA, LYGIE - Institute National Research Biomedical; KACITA, CRIS - Ministry Of Public Health; KOMPANY, JEAN PAUL - Institute National Research Biomedical; Hensley, Lisa; MAKANGARA-CIGOLO, JEAN-CLAUDE - Institute National Research Biomedical; KENYE, MICHEL - Institute National Research Biomedical; KAVIRA, SIFA - Institute National Research Biomedical; KALONJI, THIERRY - Ministry Of Public Health; LINSUKE, SYLVIE - Institute National Research Biomedical; MALEMBI, EMILE - Ministry Of Public Health; MUKADI-BAMULEKA, DANIEL - Institute National Research Biomedical; SABI, LILIANE - Institute National Research Biomedical; LEMAILLE, CANDICE - University Of Manitoba; MARIE, INAKA - Ministry Of Public Health; LOW, NICOLA - University Of Bern; HOFF, NICOLE - University Of California (UCLA); SHONGO, ROBERT - Ministry Of Public Health; KINDRACHUK, JASON - University Of Manitoba; RIMOIN, ANNE - University Of California (UCLA); MBALA-KINGBENI, PLACIDE - Institute National Research Biomedical

Submitted to: PLOS Global Public Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/11/2025
Publication Date: 8/1/2025
Citation: Merritt, S., Halbrook, M., Anta, Y., Mukadi, P., Hasivirwe Vakaniaki, E., Mukadi, D., Lunyanga, L., Kacita, C., Kompany, J., Hensley, L.E., Makangara-Cigolo, J., Kenye, M., Kavira, S., Kalonji, T., Linsuke, S., Malembi, E., Mukadi-Bamuleka, D., Sabi, L., Lemaille, C., Marie, I., Low, N., Hoff, N.A., Shongo, R., Kindrachuk, J., Rimoin, A.W., Mbala-Kingbeni, P. 2025. A peer-educator driven approach for sampling populations at increase mpox risk in the Democratic Republic of the Congo: Implications for surveillance and response. PLOS Global Public Health. 5(8). Article e0003857. https://doi.org/10.1371/journal.pgph.0003857.
DOI: https://doi.org/10.1371/journal.pgph.0003857

Interpretive Summary: With the concurrent mpox outbreaks being reported in the Democratic Republic of the Congo (DRC) in 2024, and the evolving risk factors associated with both Clade 1a and 1b mpox, sampling and reaching historically hard-to-reach at-risk populations is of utmost importance. These populations, namely men who have sex with men and sex workers, may be at an elevated risk for mpox. However, these populations are often difficult to recruit and enroll in studies due to discriminatory socio-cultural norms or stigma. In this study, we present an approach to sampling both of these populations in three cities across the DRC. Not only do we enroll over 2800 participants, but we were also able to collect serum samples from all individuals. This sampling approach relied on both selecting specific sites for recruitment, and well-integrated peer educators who enrolled members of their community. This approach - while successful for sampling - could also be adapted to reach these very same populations for future mpox intervention and vaccine delivery.

Technical Abstract: Given the evolving epidemiological risk factors associated with mpox acquisition and severity, we assessed perceived mpox risk, and behavioral, clinical and sexual histories among at-risk and key populations in the Democratic Republic of the Congo (DRC). Here, we outline a sampling strategy to enroll participants considered to be at increased risk for mpox infection - men who have sex with men (MSM) and sex workers (SW) - in three urban centers in the DRC. Through the combined approach of time-location sampling with peer educators and snowball sampling following recruitment, a mixed cohort of 2826 individuals including self-identified MSM (n = 850), SW (n = 815), both MSM and SW (n = 118) and non-MSM, non-SW individuals (n = 1043) were enrolled in Kinshasa, Kinshasa province, Kenge, Kwango province, and Goma, North Kivu province, from April-August 2024. Of these, over 90% were recruited through peer educators. The odds of sampling SW individuals was significantly higher at bars/clubs than traditional health facilities. Conversely, the odds of recruiting MSM were highest at selected health facilities. Modifications to the sampling approach were introduced in Kenge and Goma, yet these did not affect the recruitment of MSM or SW participants. Ultimately, the selection of, and collaboration with well-integrated peer educators was the most important facet of this sampling strategy. As the definitions of at-risk populations continue to change for mpox, we demonstrate a method that provides a functional approach to quickly surveying otherwise hard-to-reach groups for both public health surveillance activities and response.