The Epidemiology of HIV/AIDS in Los Angeles County

As the AIDS epidemic enters its third decade, only New York City and five states, including California, have reported more cases than Los Angeles County, Calif. Over 27,000 Angelenos have died of AIDS since the epidemic began in 1981, a 62 percent fatality rate. Estimates of new HIV infections in the county remain stable at 1,500-2,000 per year. However, there are disturbing indicators that high-risk sexual behavior -- and consequently HIV infection rates -- may be on the rise, especially among young men who have sex with men (MSM).

More people than ever before, some 16,400, are now living with AIDS in Los Angeles, due to successful antiretroviral treatments and declining death rates. An estimated 30,000-45,000 people in the county are living with HIV, and approximately one-third do not know they are infected. AIDS in Los Angeles remains largely an epidemic of MSM. Although injection drug use is a less common route of transmission in Los Angeles than for the nation as a whole, it remains the second leading cause of HIV infection in the county and state. Moreover, the use of other drugs, most notably methamphetamines or "crystal," is also believed to contribute to unsafe sex and, as a result, HIV infection.

Relative to the United States as a whole, women represent a smaller percentage of all AIDS cases reported in Los Angeles and California since 1981. However, this is changing. In 2000, women accounted for nearly one-quarter of newly reported AIDS cases in the United States and 15 percent of new cases in Los Angeles County. Some 46 percent of cumulative AIDS cases among women in Los Angeles are attributed to sexual contact with an HIV-infected or at-risk partner. The rate of newly reported AIDS cases per 100,000 for African-American women in Los Angeles in 2000 was 10 times the rate for white women, and four times the rate for Latinas. In Los Angeles in 2000, African-American men reported new cases of AIDS at nearly four times the rate of whites, and about twice the rate for Latinos.

Latinos emerged as the largest single group among newly diagnosed cases of AIDS in Los Angeles County in 1997, in part due to their significant population growth. While Latinos are now the largest ethnic group in the county, they are somewhat underrepresented as a percentage of cumulative AIDS cases and people living with AIDS. However, in 2000, they accounted for 44 percent of newly diagnosed AIDS cases in the county, nearly matching their percentage of the population. Nationally, Latinos represent approximately 14 percent of the US population (including Puerto Rico) and 19 percent of new AIDS cases reported in 2000.

Within Los Angeles County, the highest AIDS case rates, both historically and currently, are found in the West Hollywood, Hollywood, and Silverlake axis. Downtown Los Angeles, South Central, and the South Bay -- especially Long Beach -- also have high incidences of new cases. Because of Los Angeles' proximity to the US-Mexico border, AIDS in Los Angeles is also inextricably linked with the AIDS epidemic in Mexico and Central and South America. Some 3 million immigrants from nearly 100 countries have arrived in Los Angeles since 1980. An estimated 21 percent of all people in Los Angeles County diagnosed with AIDS were born outside the United States. Of these, half were born in Mexico. As in Los Angeles, AIDS in Mexico is largely an epidemic of MSM. An estimated 14 percent of Mexican MSM are living with HIV.

As new treatments have substantially increased the average lifetime of a person infected with HIV, AIDS data are less able to reflect the full scope of the epidemic. This year, California will begin implementing a non-names based HIV reporting system to track HIV infections. This new system will provide public health officials and community planners with important new data without compromising individuals' confidentiality, which would likely discourage testing.

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