CDC NATIONAL AIDS HOTLINE TRAINING BULLETIN #10 - June 18, 1992
Centers for Disease Control and Prevention

1. What is it (HIV-2)?

HIV-2 is a virus similar in structure to HIV-1. Infection with HIV-2, which also causes AIDS, is very rare in the United States, but relatively common in West Africa. The Centers for Disease Control and Prevention (CDC) began surveillance of HIV-2 in the United States in 1987. As of December 1991, there were 32 known cases of HIV-2 infection among persons living in the United States. All of these cases are among persons originally from West Africa or who have a connection with West Africa.

2. Where can I get tested?

The Genetic Systems HIV-2 enzyme immunoassay (EIA) was licensed by the US Food and Drug Administration (FDA) in 1990. This test should be available commercially or through state and local health departments. HIV-2 testing is indicated in persons with risk factors for HIV-2 infection--West Africans, sexual partners of West Africans, persons who have received blood transfusions in West Africa, children born of HIV-2-infected mothers. HIV-2 testing is also indicated in persons with an illness that suggests HIV infection (such as an HIV-associated opportunistic infection) in whom HIV-1 testing is not positive.

3. Is the antibody development period the same?

Testing of persons infected with HIV-2 show a similar antibody development to persons infected with HIV-1.

4. What is the incubation period? The media said it is 19 years.

Some reports have shown a long incubation in some patients. However, there is not enough information on the natural history of HIV-2 to give an average incubation time.

5. What are the symptoms?

Since HIV-2 also causes immunodeficiency in infected persons, some of the symptoms will probably be similar to those of HIV-1. However, as with HIV-1, symptoms alone cannot tell whether or not a person is infected with HIV-2.

6. A local T.V. station reported that it is a new AIDS virus. Is that true?

No. HIV-2 was first discovered in West African prostitutes in 1985 and isolated from AIDS patients in West Africa in 1986. Blood samples, collected in 1984 in Europe, have shown HIV-2 antibodies when tested at a later time.

7. Does the Red Cross routinely screen for HIV-2?

FDA mandated that by June 1, 1992 US blood centers must implement testing of all blood donations for antibodies to HIV-2. Some blood banks and plasma centers have already begun testing potential donors for HIV-2. Only one HIV-2 positive blood donor has been found through random testing of the blood supply. In the past, most major blood screening programs in this country and Europe have relied on the cross-reactions (from 42% to 92%) on HIV-1 antibody tests to detect infection with HIV-2.

8. Why is it so rare here? Are there any projections for an increase in infection?

The answers to these questions are unknown. Surveillance shows that HIV-2 appears to be rare in the United States. The possibility for further spread of HIV-2 exists if this virus takes hold among injecting drug users, thereby creating potential spread to their partners and children. If prevention programs for HIV-1 are used by everyone, these programs can also educate persons to prevent the spread of HIV-2.

9. Is it transmitted the same way?

All scientific/medical evidence appears to show that HIV-2 is spread the same way as HIV-1.

10. Does HIV-2 lead to AIDS?

Yes.

Questions from information specialists:

1. What are appropriate referrals for testing and more basic information?

Similar to testing for HIV-1 infection, persons being tested for HIV-2 infection are initially tested with an EIA that is sensitive for HIV-2, followed by supplemental testing of specimens that are repeatedly reactive by the HIV-2 EIA.

There are currently no licensed supplemental (confirmatory) tests (such as an HIV-2 western blot) for HIV-2 infection, so confirmation of a reactive HIV-2 EIA requires referral of a serum specimen to a reference laboratory that can perform further (unlicensed) tests. CDC requests that specimens requiring supplemental testing for HIV-2 be referred to laboratories at state and local health departments for such testing. CDC will act as a consultant to the state and local health departments.

Two EIAs that are sensitive for antibodies to both HIV-1 and HIV-2 have been licensed by FDA. Specimens that are reactive by HIV-1/HIV-2 EIA should next be tested by HIV-1 western blot. Specimens that are positive by HIV-1 western blot require no further testing. Specimens that are negative or indeterminate by HIV-1 western blot should be tested by HIV-2 EIA. HIV-2 confirmatory testing should be reserved for specimens that are repeatedly reactive by HIV-2 EIA.

2. Is it still true that HIV-2 infection has not been traced to a blood transfusion?

Yes. Because of early implementation of blood donor deferral and HIV antibody testing, the nation's blood supply is considered extremely safe. CDC studies have shown that HIV-2 is very rare among blood donors. Most blood donors who test positive by HIV-2 EIA are actually false positive.

However, CDC recommends that their serum be referred for HIV-2 supplemental testing.

Additional reading information:

CDC. Update: HIV-2 infection in the United States. MMWR;1989:572-574,579-580.

CDC. Surveillance for HIV-2 infection in blood donors - United States, 1987-1989. MMWR;1990:829-831.

George JR, Rayfield MA, Phillips S, et al. Efficacies of US Food and Drug Administration-licensed HIV-1-screening enzyme immunoassays for detecting antibodies to HIV-2. AIDS 1990;4:321-6.

O'Brien TR, George JR, Holmberg SD. Human immunodeficiency virus type 2 infection in the United States: epidemiology, diagnosis, and public health implications. JAMA 1992; 267:2775-9.

O'Brien TR, Polon C, Schable CA, et al. HIV-2 infection in an American. AIDS 1991;5:85-8.

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