Expert Analysis
Expert Analysis: Insights for International Clinicians on New Data From CROI 2020

Released: April 21, 2020

Expiration: April 20, 2021

Josep M. Llibre
Josep M. Llibre, MD, PhD
Laura Waters
Laura Waters, FRCP, MD

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TAIPAN: Correlations Between Community Viremia and HIV Incidence in Gay and Bisexual Men in Australia

Josep M. Llibre, MD, PhD:
TAIPAN, a prospective, longitudinal cohort study conducted from 2012-2017 in Australia, examined the correlation between community HIV viremia and the incidence of new diagnoses of HIV infection (Capsule Summary).19. This study was conducted in New South Wales and Victoria, which represents 57% of Australia’s population and approximately 80% of the gay and bisexual male population. In total, 115,982 men reporting same-sex partners who were both HIV positive and HIV negative were included in the study.

TAIPAN: Clinical HIV-1 RNA Levels and Rate of Undiagnosed HIV Among Australian Gay and Bisexual Men

Josep M. Llibre, MD, PhD:
The study investigators found an excellent correlation between community HIV viremia and HIV incidence. Indeed, community viremia decreased from 28.6% in 2012 to 12.8% in 2017, and HIV incidence decreased from 0.88/100 patient-years in 2012 to 0.22/100 patient-years in 2017. Both of these decreases were statistically significant and the correlation between the two, as measured by the correlation coefficient, was very strong with an r value of 0.94.

Of interest, the investigators were able to show that community viremia strongly correlated with HIV incidence independent of pre-exposure prophylaxis (PrEP) because the administration of PrEP only began in 2015. Therefore, this is strong evidence that reducing community viral load by diagnosing and quickly starting patients on effective treatment can decrease the number of new HIV cases, even in the absence of access to PrEP.

TAIPAN: Clinical Implications

Laura Waters, MD:
This study is important because it is often difficult to tease out the relative contribution of different interventions to reducing HIV incidence when they are used in combination. The debate in the United Kingdom is whether HIV testing frequency, PrEP use, or effective HIV treatment has the largest effect, and these results would suggest that the impact of treatment on population viral load is key, although testing is obviously very important as well. I think these are great data that support the approach we have been taking and show the true population impact of a comprehensive treatment program.

Josep M. Llibre, MD, PhD:
I do think that all 3 interventions matter. For instance, data from London have shown that PrEP can have an impact on the incidence of HIV.20

Laura Waters, MD:
One of the challenges we have had in the United Kingdom, in terms of PrEP, is how to reach certain groups, particularly those who have migrated from other countries. Often the assumption is that people with HIV who have migrated into the United Kingdom from higher-prevalence settings were already HIV positive at entry. However, that is not correct, and it is estimated that at least one half actually acquire HIV post migration. That is a group we urgently need to target because it is almost entirely preventable. It is possible that we could have an impact by counseling about HIV acquisition and PrEP upon entry into the country.