A review of data reported to the National HIV Surveillance System through June 2016 suggests that a single measure of viral load may overestimate how many persons with HIV infection have durable viral suppression. The data also showed that some persons who seemed to have received regular care for HIV infection still had viral loads high enough to substantially increase transmission risk. The brief report is published in Annals of Internal Medicine.
Researchers from the Centers for Disease Control and Prevention (CDC) reviewed data for 630,965 persons aged 13 years or older who were diagnosed with HIV infection through 2013 to determine the usefulness of a single measure of viral load for understanding long-term suppression and to examine the extent of cumulative HIV burden for understanding the potential risk for transmission. The researchers used information about sex, age, transmission category, and race/ethnicity to calculate the percentage of persons with HIV infection whose last viral load in 2014 was less than 200 copies/mL. They also calculated the percentage of persons in whom all viral loads in 2014 were less than 200 copies/mL (durable viral suppression), the percentage of persons in whom all viral loads in 2014 were 200 copies/mL or greater (viral suppression never achieved), and "copy year," which is a measure of viremia that assesses a person's exposure to HIV over time similar to the way pack-years measures a person's exposure to tobacco smoke over time.
The data showed that of all persons with HIV infection, 57.3 percent had a suppressed viral load on their most recent test in 2014, a total of 47.6 percent had durable viral suppression throughout 2014, and 8.1 percent never achieved viral suppression during 2014. Those who never achieved viral suppression in 2014 had an average of 17,530 copy-years of viremia and 56.3 percent of those people had at least two tests for viral load in 2014, suggesting that they had regular care for their infection. The findings emphasize the importance of routine monitoring of viral suppression status and of more effective delivery of appropriate therapy in response to the results of such monitoring.