The overall amount of time that people receiving care for HIV in the United States spend with a viral load above 1,500 has fallen by about three quarters since the turn of the millennium, aidsmap reports. This viral load threshold represents the point above which HIV is considered significantly infectious, since there have been few documented cases of transmission from people with viral loads below that level.

Centers for Disease Control and Prevention (CDC) researchers analyzed 2000 to 2014 data on the viral load status of 5,873 people in HIV care in nine U.S. cities who were members of the HOPS cohort.

Findings were presented at the 2017 Conference on Retroviruses and Opportunistic Infections (CROI) in Seattle.

The participants were followed for a median 5.4 years and a cumulative 37,794 years. They received an average of 15 viral load tests, spaced a median 3.6 months apart.

Overall, 86 percent of the group’s time was spent receiving antiretroviral treatment and 14 percent was spent off ARVs. Four percent of people were not on ARVs but nevertheless spent some of their time with viral loads below 1,500.

In 2000, 36 percent of the cohort’s overall time, including among those not on ARVs, was spent with viral loads above 1,500. This proportion rose to 40 percent in 2003 and subsequently declined steadily to 10 percent in 2014.

The first year of the study period, 90 percent of the cohort’s time was spent on ARVs, a figure that dropped to 80 percent in 2003 to 2004 and rose to 93 percent in 2014. Of note, in 2006, the landmark findings of the SMART trial found that taking so-called structured treatment interruptions from ARVs was found to be associated with numerous negative health repercussions. Before that time, it was rather in vogue for people with HIV to take “drug holidays” for periods to avoid the considerable side effects of the standard ARVs of that era.

Among those taking ARVs, 31 percent had a viral load above 1,500 in 2000, a figure that dropped to 7 percent in 2014.

After adjusting the data for various factors, the researchers found that for every 10 years of increasing age, the cohort members were 9 percent less likely to have a viral load above 1,500; those younger than 35 who were on ARVs were 50 percent more likely to lack such viral suppression than those older than 50; those with public health insurance were 24 percent more likely to have a viral load above that threshold compared with those with private health insurance; and Blacks were 19 percent more likely than whites to have a viral load above 1,500.

To read the aidsmap article, click here.

To read the conference abstract, click here.

To view a webcast of the conference presentation, click here.