Who should be tested for HIV-2?
Because epidemiologic data indicate that the prevalence of HIV-2 in the
United States is very low, CDC does not recommend routine HIV-2 testing at U.S.
HIV counseling and test sites or in settings other than blood centers. However,
when HIV testing is to be performed, tests for antibodies to both HIV-1 and
HIV-2 should be obtained if demographic or behavioral information suggests that
HIV-2 infection might be present.
Persons at risk for HIV-2 infection include
- Sex partners of a person from a country where HIV-2 is endemic (refer to
countries listed earlier)
- Sex partners of a person known to be infected with HIV-2
- People who received a blood transfusion or a nonsterile injection in a
country where HIV-2 is endemic
- People who shared needles with a person from a country where HIV-2 is
endemic or with a person known to be infected with HIV-2
- Children of women who have risk factors for HIV-2 infection or are known to
be infected with HIV-2
HIV-2 testing also is indicated for
- People with an illness that suggests HIV infection (such as an
HIV-associated opportunistic infection) but whose HIV-1 test result is not
- People for whom HIV-1 Western blot exhibits the unusual indeterminate test
band pattern of gag (p55, p24, or p17) plus pol (p66, p51, or p32) in the
absence of env (gp160, gp120, or gp41)
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.