New HIV Cases, Death Rate and Viral Loads Dropping in Seattle Area

From 2004 through 2013 in King County, Washington State, the number of new HIV cases fell by 28%, and from 2006 through 2013 the proportion of HIV-positive people with an undetectable viral load jumped from 45% to 86%.¹ These two large changes may well be related because people with an undetectable viral load have a much lower chance of passing HIV to sex partners -- and a lower number of sex partners getting HIV infection would translate into fewer new HIV infections.

The United States has a National HIV/AIDS Strategy with several aims, including (1) cutting the number of new HIV infections across the country, (2) improving access to care and the impact of care among people with HIV, and (3) lowering differences in HIV-related health measures between different groups with HIV, such as different racial and ethnic groups.² The U.S. Centers for Disease Control and Prevention (CDC) reported a recent drop in new HIV cases across the country, but that drop was not consistent across the different groups analyzed.³ In particular, new HIV cases remained steady among gay men and other men who have sex with men -- and this group accounts for most new HIV infections in the United States.

King County, Washington, which includes Seattle, keeps detailed HIV and AIDS records, including the proportion of HIV-positive people with an undetectable viral load. Researchers in King County conducted this study to chart trends in HIV and AIDS numbers, including viral load, from 2004 through 2013.

How the Study Worked

Researchers collected King County data on HIV diagnoses (first positive HIV test), AIDS diagnoses, deaths, CD4 counts, and viral loads, all of which must be reported to state health authorities. CD4 counts and viral loads were available from 2006 through 2013, while data on HIV diagnoses, AIDS diagnoses, and deaths were analyzed from 2004 through 2013.

The investigators gathered U.S. Census data to establish the age, race or ethnicity, and place of birth of people diagnosed with HIV infection. The researchers divided people into three HIV risk groups: heterosexuals, men who have with men, and people who inject drugs and are not men who have sex with men. They calculated death rates of HIV-positive people according to 10-year age groups. They defined HIV control as a viral load below 200 copies.

What the Study Found

The study included 9539 people who had HIV infection in King County at any point from 2004 through 2013, including 1036 women (11%), 8503 men (89%), and 6365 gays and other men who have sex with men (67%). Almost two thirds of these people (64%) were white, 18% black, and 11% Hispanic.

The proportion of HIV-positive people with a viral load below 200 copies rose from 45% in 2006 to 74% in 2009 and to 86% in 2013 (Figure 1). This rising rate of viral control held true for both men and women, for all age groups, and for all HIV risk groups (heterosexuals, men who have sex with men, and people who inject drugs). From 2006 through 2013, the proportion of people with a viral load below 200 rose from 44% to 88% among whites, from 45% to 81% among blacks, and from 54% to 86% among Hispanics.

At the last CD4 count reported, the proportion of people with a CD4 count of 350 or higher climbed from 54% in 2006 to 79% in 2013. The proportion of people with a CD4 count of at least 350 over those years rose from 57% to 81% among whites, from 51% to 73% among blacks, and from 51% to 75% among Hispanics.

During the study period 3779 people tested positive for HIV. From 2004 through 2013, the new-HIV rate fell 28% from 18.4 to 13.2 cases per 100,000 people (Figure 2). The new-HIV rate fell in all HIV risk groups -- down 17% in heterosexuals, 26% in men who have sex with men, and 79% in people who inject drugs. Among MSM, the new-HIV rate dropped 16% in those younger than 30 years old, 51% in those 30 to 39 years old, and 44% in those 40 to 49 years old. The new-HIV rate fell 39% among blacks, 27% among whites, and 25% among Hispanics. The new-HIV rate dropped 26% from 6.2 to 4.6 per 1000 people in white men who have sex with men, 22% from 10.7 to 8.3 per 1000 people in Hispanic men who have sex with men, and 44% from 17.9 to 10.0 per 1000 people in black men who have sex with men.

From 2004 through 2013, new AIDS cases fell 42% from 12 to 7 per 100,000 people. The drop in new AIDS cases in this period measured 37% in men who have sex with men, 82% in people who inject drugs, and 35% in heterosexuals. Over the same period, the annual death rate fell 28% from 16 to 12 deaths per 1000 people with HIV/AIDS. The death rate fell 32% in men who have sex with men, 20% in people who inject drugs, and 21% in heterosexuals. The death rate dropped 33% among whites with HIV, 73% among blacks with HIV, and 33% among Hispanics with HIV.

What the Results Mean for You

These encouraging findings show good progress in preventing and controlling HIV infection in Washington State's King County. No group got left behind in these year-to-year measures of viral load, CD4 count, new HIV infections, new AIDS cases, and deaths: Rates improved in men and women; in blacks, whites, and Hispanics; and in heterosexuals, men who have sex with men, and people who inject drugs.

The individual measures analyzed are probably connected in several ways. For example, increasing proportions of people with an undetectable viral load and high CD4 count translate into fewer AIDS cases and fewer deaths among people with HIV. A growing proportion of HIV-positive people with an undetectable viral load means fewer people with HIV will pass HIV to sex partners or drug-injecting partners. As a result, the rate of new HIV infections should drop, and in turn the number of new AIDS cases and the number of deaths should fall.

People with HIV should remember that starting antiretroviral therapy, taking antiretrovirals consistently, and reaching an undetectable viral load have two major benefits: First, the individual benefits by returning to health and living a longer, productive life. And second, the community benefits because HIV-positive people with undetectable viral loads rarely pass HIV to uninfected people. That doesn't mean HIV-positive people with an undetectable viral load can stop using condoms: Condoms remain important barriers to other sexually transmitted infections that might pass from one partner to another during sex.

Men who have sex with men account for the biggest share of HIV infections in the United States. Across the country the new HIV infection rate has begun to drop -- but not among men who have sex with men.³ This study in the Seattle area1 shows that new HIV cases can fall sharply in men who have sex with men -- 26% in this analysis -- in areas where public health officials, community-based groups, HIV providers, and individuals cooperate to limit new HIV infections. A recent study in San Francisco charted a 46% drop in new HIV infections among men who have sex with men⁴ -- for some of the same reasons that this rate fell in the Seattle area.¹

This study in Seattle and surrounding King County shows that everyone can benefit from better HIV care, better viral load control, and other factors analyzed in this report.¹ Everyone with HIV or at risk of HIV infection can benefit when a community works together to control HIV.

References

1. Golden MR, Bennett AB, Dombrowski JC, Buskin SE. Achieving the goals of the National HIV/AIDS Strategy: declining HIV diagnoses, improving clinical outcomes, and diminishing racial/ethnic disparities in King County, WA (2004-2013). Sex Transm Dis. 2016;43:269-276.
2. White House Office on National AIDS Policy. National HIV/AIDS Strategy for the United States. Washington, DC: White House Office on National AIDS Policy. 2010.
3. Johnson AS, Hall HI, Hu X, et al. Trends in diagnoses of HIV infection in the United States, 2002-2011. JAMA. 2014;312:432-434.
4. Das M, Chu PL, Santos GM, et al. Decreases in community viral load are accompanied by reductions in new HIV infections in San Francisco. PLoS One. 2010;5:e11068.