HIV-2 testing also is indicated for continued...
Among all HIV-infected people, the prevalence of HIV-2 is very low compared
with HIV-1. However, the potential risk for HIV-2 infection in some populations
(such as those listed) may justify routine HIV-2 testing for all people for
whom HIV-1 testing is warranted. The decision to implement routine HIV-2
testing requires consideration of the number of HIV-2-infected persons whose
infection would remain undiagnosed without routine HIV-2 testing compared with
the problems and costs associated with the implementation of HIV-2 testing.
The development of antibodies is similar in HIV-1 and HIV-2. Antibodies
generally become detectable within 3 months of infection. Testing for HIV-2
antibodies is available through private physicians or state and local health
Are blood donors tested for HIV-2?
Since 1992, all U.S. blood donations have been tested with a combination
HIV-1/HIV-2 enzyme immunoassay test kit that is sensitive to antibodies to both
viruses. This testing has demonstrated that HIV-2 infection in blood donors is
extremely rare. All donations detected with either HIV-1 or HIV-2 are excluded
from any clinical use, and donors are deferred from further donations.
Is the clinical treatment of HIV-2 different from that of HIV-1?
Little is known about the best approach to the clinical treatment and care
of patients infected with HIV-2. Given the slower development of
immunodeficiency and the limited clinical experience with HIV-2, it is unclear
whether antiretroviral therapy significantly slows progression. Not all of the
drugs used to treat HIV-1 infection are as effective against HIV-2. In vitro
(laboratory) studies suggest that nucleoside analogs are active against HIV-2,
though not as active as against HIV-1. Protease inhibitors should be active
against HIV-2. However, non-nucleoside reverse transcriptase inhibitors
(NNRTIs) are not active against HIV-2. Whether any potential benefits would
outweigh the possible adverse effects of treatment is unknown.
Monitoring the treatment response of patients infected with HIV-2 is more
difficult than monitoring people infected with HIV-1. No FDA-licensed HIV-2
viral load assay is available yet. Viral load assays used for HIV-1 are not
reliable for monitoring HIV-2. Response to treatment for HIV-2 infection may be
monitored by following CD4+ T-cell counts and other indicators of
immune system deterioration, such as weight loss, oral candidiasis, unexplained
fever, and the appearance of a new AIDS-defining illness. More research and
clinical experience is needed to determine the most effective treatment for
The optimal timing for antiretroviral therapy (i.e., soon after infection,
when symptoms appear, or when CD4+ T cell counts fall below a
certain level) remains under review by clinical experts. Guidelines for the
Use of Antiretroviral Agents in HIV-Infected Adults and Adolescents, by the
Department of Health and Human Services Panel on Clinical Practices for
Treatment of HIV Infection, may be helpful to the clinician who is caring for a
patient infected with HIV-2; however, the recommendations on viral load
monitoring and the use of NNRTIs would not apply to patients with HIV-2
infection. Copies of the guidelines are available from the CDC National
Prevention Information Network (1 800 458-5231) and from its Web site
(www.cdcnpin.org). The guidelines also are available from the HIV/AIDS
Treatment Information Service (1 800 448-0440; Fax 301 519-6616; TTY 1 800
243-7012) and on the ATIS Web site (www.hivatis.org).