Review 1: "A Peer-Educator Driven Approach for Sampling Populations at Increased Mpox Risk in the Democratic Republic of the Congo: Implications for Surveillance and Response"

RR\ID Evidence Scale rating by reviewer:

• Reliable. The main study claims are generally justified by its methods and data. The results and conclusions are likely to be similar to the hypothetical ideal study. There are some minor caveats or limitations, but they would/do not change the major claims of the study. The study provides sufficient strength of evidence on its own that its main claims should be considered actionable, with some room for future revision.

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Review: The article “A Peer-Educator Driven Approach for Sampling Populations at Increased Mpox Risk in the Democratic Republic of the Congo”; explores a peer-educator driven approach for sampling key populations at increased risk of mpox infection, including men who have sex with men (MSM), sex workers (SW) and other at-risk populations (ARP). The study's conclusion emphasizes the effectiveness of this strategy in reaching potentially stigmatized populations, asserting its value for public health surveillance and response strategies. While the research presents compelling findings, its conclusions need critical examination.

The authors appropriately used peer educators (PEs) to facilitate recruitment, which is supported by previous literature suggesting community-based strategies are beneficial in reaching stigmatized, marginalized and vulnerable populations. This shows the primary role of PEs, as the study clearly illustrates by demonstrating that over 96% of participants had been referred via PEs. As a result, the distribution of the sampled population is not random and will depend on the social networks of PEs, which can generate selection bias. While this bias is acknowledged, the implications for generalizability are understated. For instance, the study primarily captures individuals within the urban centers of Kinshasa, Kenge, and Goma, potentially overlooking those in rural or less accessible areas where different transmission dynamics might exist.

The mixed use of time-location sampling (TLS) and Respondent-driven sampling (RDS) also offered a flexible framework, however the low uptake of RDS (less than 2% of recruits) calls into question how well it was integrated or effective in facilitating recruitment. According to the authors, this is due to the lack of participant incentives. They suggest that RDS utility could be enhanced through methodological refinements, though these have not yet been detailed. Similarly, although bars and health facilities were reported to be successful TLS venues for recruiting SW and MSM respectively, the absence of granular venue-level data limits the ability to evaluate specific site-level influences on recruitment success.

The inclusion of ARP participants is a notable strength, expanding the scope beyond traditionally targeted populations. However, the study lacks a clear differentiation in risk stratification between ARP groups, which would allow nuanced understanding of their susceptibility to mpox. Regarding infection risk, the reported overlap between MSM and SW groups (4.2% of respondents) suggests compounded risk but is insufficiently analyzed, leaving an important intersection under-explored.

Ethical considerations are addressed adequately, with informed consent and cultural sensitivity covering participant engagement. However, the socio-political context, including proposed anti-LGBTQ+ legislation in the DRC, adds complexity to the finding’s interpretation . The authors highlight this but stop short of discussing how such external factors might skew participant responses or willingness to engage.

In summary the paper presents evidence supporting its main argument that a peer-educator-driven approach can effectively access stigmatized and vulnerable populations for surveillance. However, its conclusions would benefit from a deeper exploration of methodological limitations, potential biases, and external contextual factors. The study offers a valuable framework for rapid data collection in resource-limited settings, but potential scalability and adaptability of this approach across diverse contexts have to be investigated.