HIV prevention essential for ending generalised epidemics, despite test and treat

Modelling from Lesotho, Mozambique and Uganda suggests that countries with generalised HIV epidemics must not rely on test and treat to end HIV. Primary prevention must be provided, even to people at lower risk of infection.

What is the research about?

The role and cost-effectiveness of HIV prevention in the context of test and treat. Test and treat provides immediate antiretroviral treatment (ART) for anyone diagnosed with HIV.

Why is this research important?

As ART has scaled up and more people have become virally suppressed, HIV infections have fallen. Some people are now questioning how much investment should be made in primary HIV prevention to stop new infections, when HIV treatment can also stop transmission.

This is a complicated area of research. It requires the use of mathematical modelling to predict how many people will be prevented from getting HIV through ART and various primary prevention interventions.

In this study, researchers used data from Lesotho, Mozambique and Uganda to assess different scenarios. Each country has a generalised HIV epidemic, which means it affects the entire population.

In one scenario, ART coverage was set at 2008 levels, before test and treat was introduced.

In a second scenario, ART coverage was set at 2019 levels, when test and treat was operational. This represents what might happen if countries do not achieve the UNAIDS’ 95-95-95 targets.

A third scenario imagined all three countries had met the UNAIDS’ targets.

Modelling tracked the impact of scaling up voluntary medical male circumcision (VMMC), PrEP and an HIV vaccine in each ART scenario in terms of preventing new infections. An HIV vaccine does not yet exist so this was a hypothetical option.

Cost per HIV infection averted was assessed over 5, 15 and 30 years.

What did they find out?

Each prevention intervention reduced new infections beyond what was achieved by ART scale-up alone, even if the UNAIDS’ goals were met.

The modelling found it was possible for primary prevention to decrease HIV infections by an additional 70–75%, compared with reductions that could be achieved by scaling up ART. Providing a combination of prevention options was more impactful than providing single interventions.

Even if the UNAIDS’s targets were met, it was only possible to reach near-zero HIV infections by providing a combination of prevention interventions for all segments of the population. Even those people deemed to be at lower risk of infection.

One-time interventions, such as VMMC provided to the general population, were found to be more cost-effective than those that need to be provided more than once, such as PrEP. As incidence declines, more expensive prevention interventions that need to be provided more than once will be cost-effective for people during phases of highest risk or in areas with high HIV incidence.

What does this mean for HIV services?

Primary HIV prevention is still essential in the era of test and treat. This is particularly important for countries that have been slow to scale up ART.

Making a wide range of HIV prevention options available is important. This could include a mix of condoms and lubricants, VMMC, varieties of PrEP (oral, topical, injectable), and eventually a vaccine.

In generalised HIV epidemics, it is also important to make HIV prevention available to a broad range of people, even if they do not appear to be at high risk.