Test Cases Suggest Near Zero Possibility of Transmitting HIV When Viral Loads Are Low

In a groundbreaking study published in The Lancet, a team of infectious diseases specialists from the Global Health Impact Group, in collaboration with a doctor from Switzerland, has shed new light on the transmission risk of HIV in individuals with low viral loads. The research suggests that individuals with HIV who maintain a viral load below 1,000 cpy/mL have an incredibly low likelihood of transmitting the virus to their sexual partners.

In the early days of the HIV/AIDS epidemic, an HIV diagnosis was almost always considered a death sentence. However, advances in medical science have led to the development of antiretroviral therapy (ART), which aims to reduce viral loads and manage the symptoms of HIV. While the disease is still incurable, it has become a survivable condition, and many infected individuals now lead healthy lives with proper treatment.

Despite the success of ART, questions have persisted about the infectiousness of individuals with low viral loads. The study conducted by Laura N. Broyles, Robert Luo, Debi Boeras, and Lara Vojnov analyzed eight separate studies conducted over a 12-year period, seeking to determine the level of risk for transmission in sexually active couples where one partner is HIV-positive and the other is not. The studies involved 7,700 couples residing in 25 different countries and were conducted between 2010 and 2022.

Among the 323 instances of infection recorded during the studies, a noteworthy finding emerged: 80% of these infections occurred in cases where the infected partner had a viral load of at least 10,000 cpy/mL. Only two instances involved patients with viral loads below 1,000 cpy/mL, and none occurred in cases where the infected partner's viral load was below 200 cpy/mL.

Based on these results, the research team suggests that individuals with viral loads between 200 and 1,000 cpy/mL have a very minimal risk of transmitting the virus to their sexual partners. Furthermore, for those with viral loads below 200 cpy/mL, the risk of transmission appears to be virtually non-existent.

The implications of this study are profound. It not only provides valuable insights into HIV transmission but also has potential implications for public health policies and guidelines surrounding HIV management. The controversial claim made by the Swiss National AIDS Commission in 2008, stating that adhering to standard antiretroviral therapy eliminates the risk of HIV transmission, gains new support from this research.

While these findings are promising, it is essential to remember that the risk of transmission is not completely eliminated, even for individuals with low viral loads. Therefore, safe sex practices and regular medical check-ups remain critical components of HIV prevention and management.

Journal Information: Laura N Broyles et al, The risk of sexual transmission of HIV in individuals with low-level HIV viraemia: a systematic review, The Lancet (2023). DOI: 10.1016/S0140-6736(23)00877-2

Linda-Gail Bekker et al, HIV is sexually untransmittable when viral load is undetectable, The Lancet (2023). DOI: 10.1016/S0140-6736(23)01519-2