Introduction: Why risk clustering matters for HIV transmission
New HIV infections have fallen in many high-prevalence countries over the past decade, but the epidemic persists in pockets where unsuppressed individuals engage in high-risk sexual behaviors. A population-based survey in KwaZulu-Natal, South Africa, sheds light on how risk factor clustering—age, sex, awareness of status, ART uptake, and viral suppression—contributes to ongoing HIV transmission in rural communities.
The study: who remains most at risk?
The analysis focused on HIV-positive individuals aged 15–59 years in the Eshowe/Mbongolwane area during 2018. Among 862 participants, 76.2% were women, and the median age was 36. Importantly, 10.1% were unaware of their HIV status, 15.8% were not on ART, and 16.3% were virally unsuppressed (viral load ≥1000 copies/mL). Of those sexually active in the prior year, 46.9% used condoms consistently, while 7.5% reported more than one partner.
When physical risk and virological data were combined, 10.6% of HIV-positive participants fell into high or very high transmission risk groups. Notably, half of this high-risk subset were unaware of their status, and about three-quarters were not on ART. Among those at very high risk (virally unsuppressed with multiple partners and inconsistent condom use), men aged 20–59 years formed the majority, and most were untreated or unaware.
Age and gender patterns: where interventions must focus
Youth aged 15–19 years showed higher rates of unawareness and viral non-suppression, regardless of gender. Across the broader 15–34 age range, men with multiple partners and inconsistent condom use emerged as a key driver group, followed by a substantial share of women in the same age window. The data indicate that:
– The very high-risk group comprises a small share (2.3%) but concentrates virally unsuppressed individuals with high-risk sexual behavior, especially men aged 20–59 years.
– Awareness and ART coverage remain uneven, with around 50% of the high-to-very-high risk group unaware of their status and three-quarters not on ART.
Implications for prevention and policy
The findings highlight several urgent needs. First, targeted HIV diagnosis and status awareness programs are essential in the age and gender bands most likely to sustain transmission—particularly young men and women aged 20–34. Second, intensified adherence support and access to second- or third-line ART are crucial to achieve and maintain viral suppression in these groups. Third, behavioral-risk reduction strategies, including reinvigorated condom promotion and testing services, must accompany treatment scale-up to reduce the potential for onward transmission among those with high-risk sexual patterns.
Although South Africa has seen declines in new infections, the study underscores that TasP (treatment as prevention) alone may not suffice if clusters of high-risk, unreconciled individuals persist. The country’s ongoing epidemic requires a nuanced strategy that prioritizes early HIV diagnosis, rapid ART initiation, robust adherence support, and culturally tailored behavioral interventions, especially for men and youth in rural KwaZulu-Natal.
Limitations and context
The data reflect a 2018 cross-sectional snapshot, and self-reported sexual behavior may be influenced by social desirability bias. Nonetheless, the study complements earlier work in the same area, showing improvements in HIV testing and ART indicators but persistent transmission risks tied to age-gender subgroups and incomplete viral suppression. The insights are valuable for designers of targeted prevention programs aiming to shrink the pool of individuals at high risk of transmitting HIV.
Conclusion: targeted, data-driven interventions are needed
To curb sustained transmission, public health efforts must combine universal testing and ART expansion with focused interventions for subgroups most responsible for continued HIV spread. Prioritizing HIV diagnosis, awareness, ART uptake, and adherence support in young adults—especially men—and sustaining condom-use promotion in high-risk groups are vital steps toward reducing HIV incidence in rural KwaZulu-Natal and beyond.
