HIV-2 Infection Among Blood and Plasma Donors--United States, June 1992-June 1995

Human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2)both cause AIDS. Following the licensure of combination HIV-l/HIV-2screening enzyme immunoassays, the FDA recommended that beginningin June 1992, all donated whole blood, blood components, and sourceplasma be screened for antibody to HIV-2, because not all personsinfected with HIV-2 can be detected by HIV-1 testing [1,2]. Thisreport describes the first two cases of HIV-2 infection detectedamong potential blood donors since the implementation of recommendedHIV-2 screening, and summarizes national data about persons knownto be infected with HIV-2 during December 1987 to June 1995.

Donor 1

In June 1994, a blood donation was discarded after it tested positiveby combination HIV-1/HIV-2 enzyme immunoassay and indeterminateby HIV-1 Western blot assay. The donor was notified about thetest results and consented to an interview and repeat testing.Testing at the CDC indicated that the specimen was positive byHIV-1 enzyme immunoassay, HIV-1 Western blot assay, HIV-2 enzymeimmunoassay, and HIV-2 Western blot assay research use only. Resultsof research use only synthetic peptide tests indicated cross-reactivityto HIV-1 and were interpreted as HIV-2 infection.

The donor was born and resided in the United States. She had notpreviously donated blood or plasma. She reported no symptoms relatedto HIV infection, and denied use of intraveous drugs, receiptof transfusions, and travel outside the United States. Since 1982,she had had four male sex partners, all born in the United States.The HIV status of her partners is unknown, and she was unawareof any HIV infection risks among them. She has no children. Shereceived HIV counseling-including instructions to refrain fromdonating blood, blood components, and tissues or organs-and wasreferred to a health-care provider.

Donor 2

In November 1994, a plasma donation was destroyed after the serumtested positive by combination HIV-1/HIV-2 enzyme immunoassayand research use only HIV-2 Western blot assay. Attempts by theplasma center to notify the donor were unsuccessful. However,the donor independently sought HIV testing 2 weeks later at acounseling and testing site. In these tests, the HIV-1 enzymeimmunoassay was positive and HIV-1 Western blot assay was atypicalwith an indeterminate band pattern suggestive of HIV-2 infection.Subsequent testing at the CDC indicated the specimen was HIV-1enzyme immunoassay positive, HIV-1 Western blot assay indeterminate,HIV-2 enzyme immunoassay positive, and HIV-2 Western blot assaypositive. Research use only synthetic peptide enzyme immunoassayand dot blots were also positive for HIV-2. These results wereinterpreted as confirming HIV-2 infection.

During the follow-up interview, the male donor reported no symptomsof HIV infection. He had not previously donated blood or plasma.He was born in France and had lived in several countries in westernAfrica during 1979-1985, before moving to the United States. Whilein western Africa, he was vaccinated on two occasions with needlesthat were wiped with cotton and reused between patients. He alsoreceived several tattoos in Africa. Of his estimated 35 lifetimesex partners, most were African. The donor denied having had sexwith men, using intravenous drugs, and receiving transfusions.He received HIV counseling-including instructions to refrain fromdonating blood, blood components, and tissues or organs-and wasreferred to a health-care provider.

US Reports of HIV-2 Infection

As of June 30, 1995, a total of 62 persons with HIV-2 infectionwere reported in the United States (Figure 1). Of 58 persons forwhom gender data were available, 38 (66%) were male. At least11 of the 62 persons had an AIDS-defining condition at the timeof report, and 5 are known to have died. Of these 62 persons,42 (68%) were born in western Africa and 2 in Europe; for 9, theregion of origin was unknown, although 4 had malaria antibodyprofiles consistent with previous residence in western Africa.Of the nine persons with HIV-2 infection born in the United States,six were adults, of whom four had either traveled to or had asex partner from western Africa, and three were infants born tomothers of unknown national origin.

Editorial Note from the CDC

In the United States, HIV-2 infection among blood donors is extremelyrare. Since the implementation of combination HIV-1/HIV-2 enzymeimmunoassay screening of blood and plasma donations, an estimated74 million donations have been tested for HIV. Including the twocases described in this report, three cases of HIV-2 infectionhave been detected among blood and plasma donors in the UnitedStates; the first case was detected by HIV-1 screening in 1986[3]. These findings are consistent with previous surveys of approximately20 million US blood donations during 1987-1989, in which no blood-donorspecimens with HIV-2 antibody were detected [4,5].

The national blood supply is protected from HIV primarily throughtwo methods:

• Interviewing donors about risk behaviors for HIV infection
• Laboratory screening donations for HIV [6,7].

All donations detected with HIV are excluded from any clinicaluse (21 CFR 610.45(c)) , and donors are deferred from furtherdonations (21 CFR 606.160(e)). For both donors describedin this report, although no HIV risk factors were identified duringthe interview preceding blood donation, laboratory screening oftheir blood and plasma donations detected HIV infection. Subsequenttesting revealed HIV-2 cross-reactivity, resulting in a positiveHIV-1 enzyme immunoassay (which would have led to exclusion evenin the absence of HIV-2 testing) and a positive or indeterminateHIV-1 Western blot assay.

Human immunodeficiency virus type 1 is distributed worldwide andis prevalent in the United States; however, HIV-2 is endemic inwestern Africa, with limited distribution to other regions ofthe world. Of the 62 persons reported with HIV-2 infection inthe United States, at least 48 (77%) were born in, had traveledto, and/or had a sex partner from western Africa.

In addition to detection of HIV-2 cases through blood and plasmadonor screening, epidemiologic data about HIV-2 cases are collectedthrough the CDC-supported national HIV/AIDS surveillance systemand serosurveys [8,9]. Because not all persons who are infectedwith HIV-2 donate blood or are otherwise tested for HIV-2, thenumber of persons reported with HIV-2 infection probably is underestimated.Nonetheless, the data from these sources indicate that HIV-2 isuncommon in the United States.

Blood centers detecting a repeatedly reactive specimen by combinationHIV-l/HIV-2 enzyme immunoassay should follow the recommended CDC/FDAtesting algorithm [1]. Specimens suspected of being HIV-2 positivemay be referred to state health department laboratories or tothe CDC for confirmatory HIV-2 testing. Cases of HIV-2 infectionshould be reported to state and local health departments, as allowedby law and/or regulation. Periodic updates about the number ofpersons known to be infected with HIV-2 in the United States areavailable from the CDC National AIDS Clearinghouse.

References:

1. CDC: Testing for antibodies to human immunodeficiency virustype 2 in the United States. Morbid Mortal Weekly Rep 41(RR-12),1992.

2. George JR, Rayfield MA, Phillips S, et al: Efficacies of USFood and Drug Administration-licensed HIV-1-screening enzyme immunoassaysfor detecting antibodies to HIV-2. AIDS 4:321-326, 1990.

3. O'Brien TR, Polon C, Schable CA, et al: HIV-2 infection inan American. AIDS 5:85-88, 1991.

4. CDC: Surveillance for HIV-2 infection in blood donors-UnitedStates, 1987-1989. Morbid Mortal Weekly Rep 39:829-831, 1990.

5. CDC: AIDS due to HIV-2 infection-New Jersey. Morbid MortalWeekly Rep 37:33-35, 1988.

6. Food and Drug Administration: Revised Recommendations for thePrevention of Human Immunodeficiency Virus (HIV) Transmissionby Blood and Blood Products (memorandum to all registered bloodestablishments). Bethesda, Maryland, US Department of Health andHuman Services, Public Health Service, Food and Drug Administration,Center for Biologics Evaluation and Research, 1992.

7. Food and Drug Administration: Recommendations for Donor ScreeningWith a Licensed Test for HIV-1 Antigen (memorandum to all registeredblood and plasma establishment). Rockville, Maryland, US Departmentof Health and Human Services, Public Health Service, Food andDrug Administration, Center for Biologics Evaluation and Research,1995.

8. CDC: HIV/AIDS Surveillance Report, vol 6, no 2, pp 36-37. Atlanta,Georgia, US Department of Health and Human Services, Public HealthService, 1995.

9. O'Brien TR, George JR, Holmberg SD: Human immunodeficiencyvirus type 2 infection in the United States. JAMA 267:2775-2779,1992.