HIV Epidemiology and Key Population Dynamics

HIV remains a major global health challenge, with the burden of infection concentrated in both generalised and concentrated epidemics. Generalised epidemics are driven by widespread transmission across the adult population, whereas concentrated epidemics persist primarily among key populations at elevated risk—such as female sex workers (FSWs), men who have sex with men (MSM), people who inject drugs (PWID), transgender individuals and clients of sex workers. Patterns of prevalence and incidence vary by region, influenced by sociocultural factors, stigma, legal frameworks and access to prevention and treatment services. Dynamic transmission modelling and surveillance have revealed that unmet prevention and treatment needs of key populations can sustain onward transmission into broader networks. Accurate population size estimation underpins effective programme planning, guiding resource allocation and the measurement of service coverage. Advances in methodological approaches—including capture–recapture, respondent-driven sampling and geographic mapping—have improved estimates of hidden populations. Alongside biomedical interventions such as antiretroviral therapy (ART) and pre-exposure prophylaxis (PrEP), behavioural and structural measures remain central to comprehensive responses. The interplay between community engagement, legal reform and data-driven strategies is critical to curbing new infections, reducing inequalities and ultimately moving towards epidemic control at national and subnational levels.

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HIV Epidemiology and Key Population Dynamics publication trend

The graph below shows the total number of articles in hiv epidemiology and key population dynamics across all publications each year (not limited to Nature Index journals).

Technical terms

Incidence: rate of new HIV infections in a defined population over a specified time period.

Prevalence: proportion of a population living with HIV at a given time.

Key populations: subgroups at higher risk of HIV infection due to behavioural, social or legal factors, including FSWs, MSM, PWID and transgender people.

Capture–recapture method: statistical approach using multiple sampling occasions to estimate the size of hidden or hard-to-reach populations.

Respondent-driven sampling: chain-referral survey technique used to recruit members of hidden populations through peer networks.

Viral load suppression: reduction of HIV RNA in blood to undetectable levels, achieved through effective ART.

References

1. Challenges and Opportunities in Big Data Science to Address Health Inequities and Focus the HIV Response. Current HIV/AIDS Reports (2024).
2. Population Size Estimation of Men Who Have Sex With Men in Rwanda: Three-Source Capture-Recapture Method. JMIR Public Health and Surveillance (2023).
3. Population sizes, HIV prevalence, and HIV prevention among men who paid for sex in sub-Saharan Africa (2000–2020): A meta-analysis of 87 population-based surveys. PLOS Medicine (2022).