As of 2009, 33.4 million people worldwide were living with HIV, with some 2.7 million new infections each year, according to the World Health Organization. The Centers for Disease Control estimates that more than one million people in the United States alone are HIV positive, and that one in five of those individuals is unaware of his or her infection. Given the scope of the problem, slowing the spread of HIV remains a public policy issue of enormous importance.

In 2010 researchers at the British Columbia Centre for Excellence in HIV/AIDS published a study in The Lancet, “Association of Highly Active Antiretroviral Therapy Coverage, Population Viral Load, and Yearly New HIV Diagnoses in British Columbia, Canada: A Population-Based Study,” that focused on efforts to decrease the rate of new HIV infections. Conducted from 1996 to 2009, the study sought to determine if increasing the number of individuals receiving highly active antiretroviral therapy (HAART) could reduce HIV transmission in the general population. The number of individuals in the study population that received the antiretroviral therapy increased by 547%, from 837 to 5,413.

Important points noted in the study are:

• New annual HIV diagnoses fell by 52% over the course of the study, from 702 to 338 individuals a year.
• The rate of sexually transmitted infections increased in the general population during the period of the study, which implies that the decrease in new HIV diagnoses cannot be accounted for by a decrease in risky sexual behavior.
• The total number of HIV tests conducted increased steadily during the study period, further eliminating alternate explanations for the decrease in new diagnoses.

More studies are needed to pinpoint the exact relationship between broadening the scope of antiretroviral therapies and decreasing new HIV diagnoses, the researchers say. But the study states that “the available evidence strongly suggests that community viral load is a key driving force of new HIV diagnoses and can be successfully modulated through effective expansion of HAART coverage.”

Tags: drugs, medicine, HIV/AIDS