Antiretroviral Therapy for All HIV Positive People Could Reduce Transmission

By Liz Highleyman

Treating all HIV positive people with antiretroviral therapy could reduce the rate of HIV transmission by as much as 70%, according to a study presented at the XVI International AIDS Conference and published in a special August 5, 2006 issue of The Lancet devoted to HIV/AIDS

Effective HAART can help reduce the rate of infection by lowering viral load, which dramatically decreases the risk of transmission, for example through unprotected sexual activity or sharing drug injection equipment; however, cases of transmission from individuals with undetectable plasma HIV RNA have been reported. The effectiveness of treatment-as-prevention has already been demonstrated in the use of AZT and other drugs to prevent mother-to-child transmission.

Julio Montaner, MD, and colleagues from the British Columbia Centre for Excellence in HIV/AIDS in Vancouver constructed hypothetical models to test the hypothesis that “treating 100% of HIV-infected individuals at once” might be an effective way to reduce the overall number of new infections over the next 40 years. The authors were particularly interested in the impact of this approach in low-income and middle-income countries.

The first model, which they dubbed the “prevention-centered model,” assumed that all infected individuals would initiate antiretroviral therapy with 1 year and that after the first year there would be no new HIV infections.

In the second, or “current-uptake model,” antiretroviral use in low-income and middle-income countries would be similar to that now observed in high-income countries such as the U.S.

The researchers used future population growth estimates from the U.S. Census Bureau and mortality rate estimates from UNAIDS and ART-LINC. The rate of future HIV infections was based on past UNAIDS estimates. Antiretroviral medications were assumed to cost U.S. $1 dollar per person per day, or $365 per year (the least expensive generic regimens run about $150 per person annually), which would increase at an inflation rate of 3% per year.

Results

• Calculations showed that 249 (range 193-371) million new HIV infections could be prevented if the prevention-centered approach were implemented instead of the current-uptake approach.
• Over 45 years, the total cost of antiretroviral therapy, using generic drugs, would be $338 (range $322-$382) billion U.S. dollars.
• This sum is less than the cost of the current-uptake scenario, which is estimated to cost U.S. $650 (range $531-$935) billion; this represents a reduction in total costs of U.S. $312 (range $209-$553) billion, or U.S. $125 (range $108-$149) per infection averted by using the prevention-centered approach.

In conclusion, the authors wrote, “We illustrate the potential maximal hypothetical benefit the wide adoption of antiretroviral therapy would have on countries with limited financial resources. Our results should encourage field-testing of a prevention-centered expansion of antiretroviral treatment as this represents a unique opportunity to control the global expansion of the HIV/AIDS pandemic.

”This study fits well with the emphasis on HIV prevention at this year’s international conference, but the proposed approach remains highly controversial.

The authors’ cost estimates include only antiretroviral medications, not health monitoring tests, healthcare infrastructure, or medical personnel. Nevertheless, they said that “[t]he short-term cost of treatment of all HIV-infected individuals would be more than offset by the number of new infections that it would prevent.

”Furthermore, it is difficult enough to ensure that everyone who has a current medical need for treatment receives it, and subjecting healthy individuals to the potential toxicities of antiretroviral therapy raises ethical concerns, which the authors acknowledged.

“The present approach to the management of HIV/AIDS is clearly not sustainable, and the status quo no longer acceptable if we hope to control the continued growth of the HIV global pandemic,” the authors wrote. “Although treating 100% of HIV-infected individuals worldwide might not be feasible or even ethically acceptable at this time, given the state of the pandemic, consideration of this possibility is worthwhile.”

8/15/06

References

R S Hogg, T Kerr, E Wood, and others. Potential impact of a prevention-centered approach to antiretroviral (ARV) use on the HIV-pandemic in low- and middle-income countries. XVI International AIDS Conference. August 13-18, 2006. Toronto, Canada. Abstract 20734