The biennial National HIV Prevention Conference, with its exclusive focus on science and the development of programs that may prevent HIV spread in the United States, was held in Atlanta in June 2005. This article will focus on national HIV epidemic trends and briefly summarize prevention interventions that might be most relevant to HIV treatment providers.

The HIV Epidemic in the United States: Current Statistics

The Centers for Disease Control and Prevention (CDC) estimates that as of the end of 2003, there are approximately 1 million persons (between 1,039,000 and 1,185,000) living with HIV in the U.S. [Glynn, Natl HIV Prev Conf 2005 Jun 12-15: (abstract T1-B1101]. This is nearly an 18% increase from the last estimate of HIV prevalence (between 850,000-950,000 persons) based on surveillance data through 2000. The increase is largely attributable to the availability of improved HIV treatment. An estimated 24% to 27% of those with HIV infection are not aware of their HIV status. African-Americans continue to bear a disproportionate burden of the U.S. HIV epidemic; Figure 1, p 5 summarizes the racial/ethnic background of those living with HIV in the U.S. Figure 2, p 5 shows the distribution of HIV by transmission category. Men comprise 74% of those living with HIV, and men with same sex contact (MSM) account for HIV transmission risk in 45% of cases overall.

Data from a behavioral surveillance survey conducted by the CDC in 5 U.S. cities (Baltimore, Los Angeles, Miami, New York, and San Francisco) indicate that African-American men are also least likely to know their infection status: Of 1,767 MSM recruited for the survey from bars, clubs and other public venues, black MSM were more than twice as likely to be HIV-infected as MSM of other races and were less likely to be aware of their infection status [Greenberg, June 13, 2005 Plenary Session; also MMWR 2005:54;597-601]. The Table below summarizes the HIV status at time of testing of the participating MSM by race/ethnicity, along with the participants’ perceived HIV status at the time of interview. Improving efforts to remove barriers to HIV testing overall, particularly focusing on African-American MSM, will be required to address this gap. Our ability to describe patterns of HIV spread in the U.S. is often limited by the lack of name-based reporting of HIV test results in a number of states. However, surveillance data from states that have name-based reporting indicate that the rate of HIV diagnoses decreased by 10% from 1994- 2003 among young U.S. females (13-24 years of age) but increased among men during the same 10-year period [Rangel, #M1-B0802]. This net increase among men over the decade occurred because a 30% decrease in new diagnoses from 1994-1998 was offset by a 41% increase from 1999- 2003. The increase among men was most marked among black MSM age 20-24 years. Behavioral and surveillance data together point to this group, African-American MSM, and teenagers and young adults in particular, as an extremely important focus for targeted prevention activities. Syphilis Trends in the United States Because syphilis and HIV often co-exist in high-risk sexual networks, patterns of syphilis spread may often provide useful indicators of high risk sexual behaviors and networks that spread HIV. The CDC reports that primary and secondary (P&S) syphilis cases rose again in 2004, with the largest increases seen among men and from urban areas [Weinstock, Natl HIV Prev Conf. 2005 Jun 12-15: (abstract no.T1-B1202]. Surveillance data (not yet final for 2004) document over 7,900 cases of P&S syphilis, at least an 11% increase over 2003. Although standard syphilis surveillance does not include behavioral data, models of male:female case ratios suggest that MSM transmission accounted for 64% of syphilis cases in 2004. The National Plan to Eliminate Syphilis from the United States set 2005 as the goal year for elimination of domestic syphilis transmission, but it appears that this important public health milestone will not be achieved.

Pre-empting HIV Spread

Traditionally, prevention of HIV spread has been hampered by a number of systemslevel barriers: Lack of name-based reporting in many states not only limits the ability of public health officials to characterize the local HIV epidemic and target resources to emerging pockets of infection but also makes partner notification impossible at a practical level. Integration of STD and HIV partner counseling and referral services (or PCRS, the current moniker in health departments for the partner notification process) has allowed for PCRS in reported HIV cases to be carried out by staff trained to conduct partner notification services for cases of infectious syphilis. However, given the natural history of HIV, HIV-infected individuals may have passed through the period of greatest infectiousness long before they learn of their diagnosis and are able to participate in PCRS. This contrasts markedly with PCRS in primary or secondary syphilis, where the clear goal is to pre-empt spread by identifying exposed contacts and rendering them noninfectious with prophylactic penicillin. However, if laboratory testing systems can be developed to identify acute HIV seroconverters, and if PCRS can be rapidly implemented, the opportunity may exist to actually preempt the spread of HIV, as we do with infectious syphilis. This model of PCRS for HIV has been adopted in North Carolina. In two separate presentations, Drs. Pilcher and Leone described the operational design and early outcomes from PCRS through the state health department program to identify and counsel acute HIV seroconverters [TR-A0201 and M3-B1602]. In this setting, there is one centralized public health laboratory that tests for evidence of HIV RNA in pooled specimens of blood from all HIV-antibody (Ab) negative individuals undergoing traditional testing at STD clinics and HIV counseling and testing centers. Individual samples from the pools that test positive are re-tested for HIV RNA. Those determined to be Ab-/RNA+ are rapidly notified (within 72 hours), interviewed about recent exposures, and referred for confirmation of HIV serostatus as well as HIV specialty clinical care (within 24 hours). Individuals recently exposed to these acute HIV seroconverters (at risk for having acquired HIV from the index or possibly the source of spread) are then located, counseled on their exposure, and offered HIV testing. Over the first 24 months of state-wide program operations, the health department has identified 43 acute HIV seroconverters through combined Ab/RNA lab testing and rapidly deployed PCRS services to reach 130 partners or persons suspected to be exposed to a case of acute HIV. Of these exposed persons, 67% accepted HIV testing, and 39% of those accepting testing were found to be infected. The group estimates that their program averted 0.24 secondary cases of HIV and 0.63 downstream cases for each acute HIV seroconverter identified. Prioritizing PCRS to those at highest risk of recent HIV transmission may be important for controlling spread of HIV and may become the operational standard for partner services.

Summary

Treatment advances have led to an increased prevalence of HIV infection in the United States over the past decade. Parallel advances in the “science” of HIV prevention and their thoughtful application will be required to prevent the continued spread of HIV infection.

20050701
JH2005-07-01

©1997-2005. The Johns Hopkins University AIDS Service, Division of Infectious Diseases. Permission to use and reproduce portions of this newsletter is hereby granted provided that author and publication are fully credited and both copyright and permission notice appear with reprinted material. Inquiries may be directed to Sharon McAvinue, Managing Editor. Website: Johns Hopkins AIDS Service.

AEGiS is a 501(c)3, not-for-profit, tax-exempt, educational corporation. AEGiS is made possible through unrestricted grants from Boehringer Ingelheim, Bridgestone/Firestone Charitable Trust, Bristol-Myers Squibb Company, Elton John AIDS Foundation, the National Library of Medicine, and donations from users like you. Always watch for outdated information. This article first appeared in 2005. This material is designed to support, not replace, the relationship that exists between you and your doctor.

AEGiS presents published material, reprinted with permission and neither endorses nor opposes any material. All information contained on this website, including information relating to health conditions, products, and treatments, is for informational purposes only. It is often presented in summary or aggregate form. It is not meant to be a substitute for the advice provided by your own physician or other medical professionals. Always discuss treatment options with a doctor who specializes in treating HIV.

Copyright ©1980, 2005. AEGiS. All materials appearing on AEGiS are protected by copyright as a collective work or compilation under U.S. copyright and other laws and are the property of AEGiS, or the party credited as the provider of the content.