The Partners in Prevention study

A year later in 2010, a sub-study of HIV transmission within a randomised controlled trial was published. The Partners in Prevention study was not designed to be a study of HIV treatment as prevention, but of aciclovir treatment of herpes as a possible HIV-prevention measure. Nonetheless a secondary finding was that ARV treatment reduced the risk of transmission by at least 92%.1

This study recruited 3381 serodiscordant couples from seven countries from south and east Africa. The primary endpoint of the study showed that aciclovir treatment had no effect on HIV transmission. However, during the two-year study, 349 people, about 10% of the total, initiated HIV treatment. Approximately half of people initiating treatment had CD4 counts under 200 cells/mm3 at initiation.

There were 103 new HIV infections in the study where the source of the HIV was the primary partner. Only one came from a partner taking ARVs. This implies a transmission rate of 0.39 per 100 person-years (1 case ÷ 256 person-years: 95% confidence interval [CI], 0.09-2.18) where the positive partner is taking ARVS. In contrast, the transmission rate where the positive partner was not taking ARVs was 2.23 per 100 person-years (95% CI, 1.84-2.70). This meant the relative risk of transmission from a partner taking ARVs, when adjusted for time on study and CD4 count, was 0.08: a 92% reduction in HIV transmission.

The single case of transmission on treatment involved a man who initiated ARVs 18 days before his nine-month study visit. At the twelve-month visit his partner tested positive for HIV, having been negative at month nine. No viral load tests were done in this study, but untreated partners were far more likely to transmit HIV if they had low CD4 counts.

This study had a number of limitations: it was observational rather than randomised, ARV status relied on self-report, and transmission and behaviour data were only followed for a maximum of two years. Using a single transmission to calculate the risk of infection by a person on ARVs involves sophisticated statistical analysis and very wide confidence intervals.

References

  1. Donnell D et al. ART and risk of heterosexual HIV-1 transmission in HIV-1 serodiscordant African couples: a multinational prospective study. Seventeenth Conference on Retroviruses and Opportunistic Infections, San Francisco, abstract 136, 2010
This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.
Community Consensus Statement on Access to HIV Treatment and its Use for Prevention

Together, we can make it happen

We can end HIV soon if people have equal access to HIV drugs as treatment and as PrEP, and have free choice over whether to take them.

Launched today, the Community Consensus Statement is a basic set of principles aimed at making sure that happens.

The Community Consensus Statement is a joint initiative of AVAC, EATG, MSMGF, GNP+, HIV i-Base, the International HIV/AIDS Alliance, ITPC and NAM/aidsmap
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This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.

NAM’s information is intended to support, rather than replace, consultation with a healthcare professional. Talk to your doctor or another member of your healthcare team for advice tailored to your situation.