For years, the conversation around sexually transmitted infections (STIs) has focused on detection and treatment. But what if we have been missing a crucial part of the story? Beyond just identifying infections, what if we could understand why some people are more vulnerable and how their immune system and microbiome interact with these infections?

That’s exactly what the Mbili Pamoja Study is set to uncover.

A Deeper Look at STI Risks

Men who have sex with men (MSM) in Kenya experience high rates of urethral and rectal STIs, particularly Chlamydia Trachomatis (CT) and Neisseria Gonorrhoeae (NG). However, majority of STI studies often focus on testing and treatment—without digging deeper into how these infections take hold and why some individuals experience more severe symptoms than others.

This study is not just about identifying STIs; It is about understanding the body’s response, the role of the microbiome, and how these factors could pave the way for better diagnostics and vaccines in the future.

The Study Plan

Funded by the National Institutes of Health (NIH) through Rush University in the USA, and conducted at Anza Mapema Centre of Excellence in Kisumu and PHDA Transform Clinic in Nairobi, the Mbili Pamoja Study will follow 500 MSM from Kisumu (n=250) and Nairobi (n=250) over one year.

Every six months, participants will undergo:

🔹 Medical history & physical examinations – to track the clinical progression of STIs.
🔹 Microbiome analysis – through penile and rectal swabs, providing insights into bacterial communities.
🔹 Mucosal immune profiling – measuring cytokines and immune markers to understand immune responses.
🔹 STI and schistosomiasis testing – with a special focus on how co-infections impact immune health.
🔹 Socio-behavioural assessments – including sexual behaviour, diet, and psychosocial factors influencing STI risk.

By integrating microbiome research, immune profiling, and clinical outcomes, researchers hope to identify key markers that influence STI acquisition and symptom severity.

Why This Matters

The end goal? Smarter prevention strategies.

If we can understand which bacterial communities increase susceptibility to infections or which immune responses fail to control STIs effectively, we can develop better diagnostics, targeted treatments, and even vaccines tailored to MSM populations.

For participants, this means not just STI testing, but a deeper understanding of their health—and for the broader public health community, it’s a chance to change how we approach STI prevention beyond just treatment.

Looking Ahead

📌 Recruitment is completed.
📌 Follow ups and data collection will continue for a year.
📌 Findings could redefine STI research and prevention strategies.

STIs are more than just infections—they tell a story of microbiomes, immune systems, and social environments. The Mbili Pamoja Study is here to decode that story, shaping the future of STI prevention and care in Kenya and beyond.