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February 5, 2001
8th Conference on Retroviruses and Opportunistic Infections Chicago, February 4-7, 2001
CDC Announces New Prevention Approach to Help Cut U.S. HIV Infections in Half
Large New Study Suggests Appropriate Range for Initiating Antiretroviral Therapy
Alarming Levels of HIV in Young Gay and Bisexual Men
Diverse HIV Strains in Central Africa Reveal Highly Evolved Disease by Mid-1980s
Diverse Global Epidemic Requires Investment in Public Health Infrastructure
CDC announces new prevention approach critical to help cut U.S. HIV infections in half
CDC has announced a new approach to HIV prevention that will involve intensive prevention outreach and services to those living with the disease. CDC estimates that new HIV infections could be cut in half in the United States by 2005, from an estimated 40,000 infections per year to 20,000 per year by:
Rob Janssen, M.D., Director of NCHSTP’s Division of HIV Prevention - Surveillance and Epidemiology, outlined the scientific basis for the approach and its estimated impact during an invited conference presentation.
SAFE, the Serostatus Approach to Fighting the HIV Epidemic, initially focuses on expanding voluntary counseling and testing programs to reach all individuals living with HIV infection, including the estimated 200,000 - 275,000 Americans who are infected with HIV, but don’t yet know it. According to Janssen, there are several reasons to intensify efforts to reach infected individuals. First, individuals who know they are infected can benefit from prophylaxis for opportunistic infections, monitoring of their immune status, antiretroviral therapy (when recommended), and, if needed, substance abuse and/or mental health treatment. Second, studies indicate that after learning their HIV status, most infected individuals take steps to protect their partners. Third, new HIV therapies, by lowering viral load, may reduce the degree of infectiousness. While antiretroviral therapy will not eliminate transmission of HIV, it could reduce it. At a population level, if risk behavior (condom use, sexual practices, and number of partners) remain unchanged, this reduction in transmissibility could significantly impact the course of the epidemic. Because antiretroviral therapy can have toxic and adverse physical side effects, decisions about when to initiate use of these drugs should be made by the person living with HIV in consultation with their physician.
CDC believes those who are unaware of their HIV status–and consequently not receiving prevention and care services–are contributing significantly to new HIV infections.
Through targeted awareness and testing programs, SAFE will focus on significantly increasing the number of infected people who learn their HIV status through voluntary testing (with a goal of 30,000 per year). High-risk individuals who test negative, particularly those whose partners are living with HIV, will be referred to prevention programs to help them stay uninfected.
The following four additional SAFE action steps target individuals who test positive for HIV:
Two of the primary goals of SAFE are to increase the proportion of HIV-infected people in the United States who know they are infected from the current 70 percent to 95 percent and to increase the proportion of HIV-infected people who are linked to appropriate care, prevention services, and treatment services from the current estimated 50 percent to 80 percent by 2005.
Strategies to increase knowledge of serostatus will focus on targeted communication efforts, expansion of neighborhood and community-based voluntary HIV testing, and more routine voluntary HIV testing in settings such as community health centers, STD clinics, and hospital emergency rooms. CDC will release updated Guidelines for HIV Counseling and Testing later this spring, that, for the first time, target private physicians as well as public clinics. CDC will work with organizations such as the Infectious Diseases Society of America to ensure widespread dissemination of the Guidelines. CDC will work with HRSA to improve linkages to medical care and will work with physicians who specialize in HIV therapy to integrate HIV prevention services into care.
SAFE expands upon existing prevention efforts, it does not replace them. Traditional HIV prevention efforts, proven to change behaviors and decrease risk among high-risk HIV-negative individuals, will remain a fundamental part of CDC’s HIV prevention portfolio.
Large new study suggests best time for initiating antiretroviral therapy
In a study of more than 5,000 patients, a team of researchers led by CDC have uncovered new evidence that may help further resolve when to initiate antiretroviral therapy in people with HIV – a point of ongoing debate in treating the disease. The study, conducted by CDC researcher Jon Kaplan, M.D. and colleagues, suggests that delaying treatment until key immune cell levels dip below 200 cells per microliter markedly increases a patient’s risk of death.
The study found that an estimated 95% of patients who began treatment at a CD4+ level of 200 or higher survived for at least two years following initiation of treatment. However, the estimated two-year survival rate declined to below 90% in patients who began treatment at a CD4+ level of 199-150, and continued to decline to as low as 65% for those with the CD4 level of 0-49 at treatment initiation. These findings suggest that treatment should not be delayed beyond the 200 CD4+ threshold.
At the same time, the study also indicates that treatment may be delayed until CD4+ levels fall below the level stated in current guidelines without significantly increasing a patient’s risk of death. Department of Health and Human Services (DHHS) recommendations call for antiretroviral therapy to be initiated when CD4+ levels fall below 500. This study found no significant difference in the rate of survival for patients initiating treatment with CD4+ levels within the range of 350-500, and indicates only mild elevations of risk for patients starting treatment between 200-350. These findings add to a growing body of research suggesting that delaying treatment until CD4+ levels fall considerably below 500 could reduce side effects and treatment resistance and potentially improve treatment adherence. Guidelines are currently being adjusted to recommend beginning treatment at a lower CD4+ level than currently recommended.
Alarming levels of HIV in young gay and bisexual men
An ongoing six-city study found more than 1 in 10 young gay and bisexual men to be infected with HIV. Preliminary findings show the highest level of HIV infection among African-American study participants, with nearly one-third testing positive for the virus. Led by CDC epidemiologist Linda Valleroy, Ph.D., the study includes results from surveys of more than 2,400 gay and bisexual men, aged 23 to 29 years. Participants were sampled at public venues in Baltimore, Dallas, Los Angeles, Miami, New York City and Seattle.
Data collected from 1998 through 2000 show overall HIV prevalence (percent living with HIV infection) to be 12.3% in this population. Gay and bisexual men of color have a higher prevalence than whites, with 30% of African Americans infected, 15.0% of Hispanics, and 7.0% of whites.
By city, prevalence ranged from 4.7% in Seattle to 18.0% in Dallas. There was a high level of risky sexual behavior in all cities. Overall 46% of participants reported unprotected anal intercourse during the previous six months, with a low of 41% and a high of 53% across the six cities, indicating that young men are at risk for becoming infected with HIV in all cities studied.
Additionally, of the 293 HIV-positive men in the study, only a small proportion (29%) were aware of their HIV infection.
HIV prevalence increased with age, with 10.2% of the 23- to 25-year olds in the study infected compared to 14.2% of the 26- to 29-year olds. In a similar CDC study conducted among 15- to 22-year-old gay and bisexual men from 1994-1998, a 7% overall HIV prevalence was found, indicating the mounting toll of infection among gay and bisexual men as they age. These findings underscore the critical need to reach gay and bisexual men early with sustained HIV prevention efforts.
Diverse HIV strains in Central Africa reveal highly evolved disease by mid-1980s
HIV had already developed into a "mature" disease in central Africa by the early to mid-1980s, as defined by a diverse array of HIV strains already present in the region, according to a CDC study led by Marcia Kalish, Ph.D. The study results also suggest the complexity of strains present in Zaire could pose a problem for vaccine development based on prevalent strains.
Researchers examining blood samples from 3,988 women living in the former Zaire detected at least eight of the known HIV-1 Group M subtypes, numerous recombinant viruses (almost 20%), and two unclassifiable strains among the samples. The existence of multiple subtypes and recombinant viruses so early in the epidemic, in a population where the prevalence of infections were between 3.5 and 5.2 percent, supports the hypothesis that the epidemic originated in west central Africa.
The existence of multiple HIV-1 subtypes in Zaire during the early 1980s also argues against speculation that the HIV-1 epidemic started as the result of contamination of oral polio vaccine (OPV) with a simian immunodeficiency virus (SIV). A previous independent study of early lots of OPV, including specimens supplied by CDC, failed to detect any evidence of SIV contamination.
Diverse global epidemic requires investment in public health infrastructure
Despite major differences in HIV transmission in different regions of the world, there are some common elements that will predict our future success in stemming the epidemic worldwide, according to a plenary presentation by Kevin DeCock, M.D., Director of CDC’s Kenya field office. A renewed commitment to public health, improving health infrastructure and expanded efforts to reach HIV-infected individuals with testing, prevention, and treatment services are critical components of a successful response, according to DeCock.
DeCock reviewed the epidemiology of HIV worldwide, but focused his presentation primarily on sub-Saharan Africa, which accounts for 70 percent of the world’s HIV and AIDS cases. According to DeCock, the HIV crisis cannot be addressed in Africa without seeing the epidemic in the context of public health in general. A reinvestment in African public health and an effort to rebuild basic infrastructure will be necessary before AIDS prevention, treatment, or even a vaccine, can make a substantial difference. As an example of this necessity, DeCock pointed to the continued challenges of ensuring blood safety and preventing mother-to-child transmission in the developing world. Health practitioners in Kenya and elsewhere, for example, cannot focus on delivering antiretroviral drugs to infected mothers, when there is no mechanism for identifying HIV-positive women, HIV/AIDS is considered differently from other diseases, basic necessities such as running water may be lacking, and infants are vulnerable to other preventable infections such as malaria.
The lack of widespread HIV counseling and testing, and the lack of interventions for infected persons, are viewed as critical barriers to prevention. While HIV counseling and testing has become routine for pregnant women in Europe and North America, for example, testing is a rarity for HIV-infected persons in Africa, where infection rates are hundreds of times greater. In addition to the lack of infrastructure for testing, DeCock points to the extreme stigma that continues to surround HIV. Working to normalize HIV testing, to improve care for HIV-infected persons, and to treat HIV as a public health issue as well as a social one are necessary for Africa to confront the epidemic, stressed DeCock.
This page last reviewed February 5, 2001