Time to reaching an undetectable viral load after testing HIV-positive fell from 13 months in 2008 to 5 months in 2012 among people starting antiretroviral therapy in San Francisco.1 Over the same years, the proportion of people who were living with HIV with an undetectable viral load jumped from 69% to 78%. Blacks, people with lower income, and people who inject drugs were less likely to reach an undetectable viral load.
In 2012 U.S. health authorities recommended that everyone with HIV take antiretroviral therapy, whatever their CD4 count.2 Two years before that, in 2010, the San Francisco Department of Public Health expanded HIV testing and offered antiretroviral therapy to anyone who tested positive at all publicly funded HIV clinics. Research shows that wider HIV testing and immediate antiretroviral therapy for all who test positive can limit the spread of HIV while preventing disease in treated people.
San Francisco researchers decided to see whether this testing and treating change in 2010 affected the overall HIV epidemic in the city. Specifically, they set out to see whether the time between testing positive for HIV and reaching an undetectable viral load changed from 2008 through 2012. They also aimed to determine whether the proportion of HIV-positive people with an undetectable viral load changed from 2008 through 2012.
How the Study Worked
Researchers focused on San Francisco residents at least 13 years old who tested positive for HIV between January 1, 2008 and December 31, 2012 or were diagnosed earlier and living as of January 1, 2008. Study participants came from the case records of the San Francisco Department of Public Health. Everyone with HIV in San Francisco must be reported to the Department of Public Health. These case records contain basic information like date of HIV diagnosis, age, race, and all CD4 counts and viral loads.
The researchers were mainly interested in time from an HIV-positive test to time of HIV control, defined as a viral load below 200 copies. The research team used a standard statistical method to identify factors that predicted time from an HIV-positive test to a viral load below 200 copies. Factors identified by this kind of analysis affect time to a viral load below 200 copies regardless of whatever other factors might affect that outcome.
The researchers were also interested in the proportion who had a viral load below 200 copies in each study year. The researchers used accepted statistical tests to determine the impact of factors like age, race, and health insurance on having a viral load below 200 copies in any study year.
What the Study Found
The first part of the study focused on 2349 people who had a first positive HIV test from January 2008 through December 2012. The number of people with a new HIV diagnosis remained fairly steady over each of those 5 years. Men made up close to 90% of people who tested positive for HIV in each study year, and about three quarters were gays or other men who have sex with men. About one quarter of study participants were younger than 30, about one third were 30 to 39, about one third were 40 to 49, and the rest were 50 or older.
About half of study participants were white, one quarter Latino, 15% black, and under 10% Asian. About one quarter of these San Franciscans had public health insurance (like Medicaid or Medicare), a little more than one third had private health insurance, and one quarter had no health insurance. About one quarter lived in a poor neighborhood, and about 10% were homeless.
The proportion of people who tested positive for HIV with a CD4 count of 500 or higher rose slowly but steadily from 2008 through 2012 (Figure 1). This finding indicates that more and more people in San Francisco are getting tested for HIV at an earlier disease stage, when antiretroviral therapy can have the greatest benefit. Over the same 5 years, the median (midpoint) number of months between a positive HIV test and a viral load below 200 copies fell from 13, to 11, to 8, to 6, and to 5 (Figure 1).
Statistical analysis involving this population pinpointed two factors that made reaching a viral load below 200 copies more likely (regardless of whatever other factors a person had): (1) being older than 29, and (2) being born outside the United States. The same analysis found four factors that made reaching a viral load below 200 copies less likely: (1) being black, (2) being a gay or bisexual man who injects drugs, (3) having no health insurance or public health insurance, and (4) being homeless. Chances of reaching a viral load below 200 copies rose significantly with each year for people who had a positive HIV test starting in 2010, the year San Francisco started recommending antiretroviral therapy for everyone with HIV, whatever their CD4 count.
Next the researchers focused on 11,787 people living with HIV at the end of 2012. Similar numbers were living with HIV in the preceding study years, 2011, 2010, 2009, and 2008. About 90% of San Franciscans living with HIV were men, about three quarters were gay or bisexual men, almost two thirds were white, and half had private health insurance.
Proportions of people living with HIV who had a viral load below 200 copies rose steadily over the study years -- 69% in 2008, 72% in 2009, 75% in 2010, 77% in 2011, and 78% in 2012 (Figure 2). Among all 11,787 people alive at the end of 2012, 86% had a viral load below 200 copies at least once during the study period.
Statistical analysis of San Franciscans living with HIV at the end of 2012 identified three factors that made a viral load below 200 copies more likely (regardless of whatever other factors a person had): (1) age over 29, (2) birth outside the United States, and (3) lowest-ever CD4 count 200-350 versus lower. The same analysis picked out five factors that independently made reaching a viral load below 200 copies less likely: (1) being black, (2) injecting drugs, (3) having public health insurance or no health insurance, (4) living in a poor neighborhood, and (5) a lowest-ever CD4 above 350.
What the Results Mean for You
This comprehensive study of people living with HIV in San Francisco from 2008 through 2012 made three major findings:
- Over those study years, a steadily growing proportion of people who tested positive for HIV still had a CD4 count above 500.
- Time between a positive HIV test and a viral load below 200 copies fell by more than half from 2008 (13 months) to 2012 (5 months).
- The proportion of HIV-positive people with a viral load below 200 copies rose steadily from 69% in 2008 to 78% in 2012.
Together these findings show that San Francisco health authorities and HIV providers are doing better encouraging people to get tested for HIV, helping people begin care for their HIV infection faster, and starting antiretroviral therapy promptly to reach an undetectable viral load. At the same time, San Franciscans at risk of HIV infection and those who test positive deserve credit for getting tested, starting care, and starting antiretroviral therapy. The United States recommends HIV testing for everyone between the ages of 13 and 64.3
In 2012 U.S. health authorities began encouraging everyone with HIV to start antiretroviral therapy, no matter how high their CD4 count.2 San Francisco started recommending antiretroviral therapy regardless of CD4 count in 2010. Quicker treatment protects HIV-positive people from HIV diseases and non-HIV diseases. In addition, by reaching an undetectable viral load sooner after they test positive for HIV, these people lower the chance that they will pass HIV to sex partners. HIV almost never passes from one person to another during sex if the HIV- positive person has an undetectable viral load. But people with HIV should still wear condoms during sex to protect themselves and their sex partners from other sexually transmitted diseases.
Some people in San Francisco were less likely to reach a viral load below 200 copies -- people younger than 30, blacks, people who inject drugs, and people with low income (those living in a poor neighborhood, the homeless, or people without private health insurance). Research shows that all these groups may share certain traits, such as difficulty keeping all medical appointments and difficulty taking antiretrovirals regularly.
Once you learn you have HIV infection and start care with an HIV provider, you have to do three things to keep your HIV under control: (1) keep all scheduled medical appointments, (2) start antiretroviral therapy, and (3) take your antiretrovirals on time, as spelled out by your HIV provider. If you have trouble meeting any of these three goals, talk to your provider about it. Your provider may be able to solve some problems, for example, by finding an antiretroviral combination that's easier for you to take. Or your provider may put you in touch with other professionals, such as case managers, who can help you address problems of daily living that can make medical care difficult.
- Schwarcz S, Hsu LC, Scheer S. Disparities and trends in viral suppression during a transition to a "test and treat" approach to the HIV epidemic, San Francisco, 2008-2012. J Acquir Immune Defic Syndr. 2015;70:529-537.
- U.S. Department of Health and Human Services. Guidelines for the use of antiretroviral agents in HIV-1-infected adults and adolescents. April 8, 2015.
- Centers for Disease Control and Prevention. HIV/AIDS. HIV basics. Testing. 2015.