Epidemiology of HIV-2 infection in the U.S, Lata Kumar MS, MPH Richard Selik MD Division of HIV/AIDS Prevention National Center for HIV/AIDS, Viral Hepatitis, STD and TB Prevention Centers for Disease Control and Prevention 2007 HIV Diagnostics Conference, Dec 5-7, 2007 The findings and conclusions in this presentation are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention.

Outline Background Methods –Diagnostic criteria Results Discussion Conclusion Recommendation

Background

–HIV-2 first isolated 1986 – West Africa –HIV-1 and HIV % homologous

HIV Groups and Subtypes Subtypes A-G HIV-1 HIV-2 HIV *HIV-1, subtype B most common in U.S. Subtypes A - K Group N Group M * Group O

Ivory Coast Guinea Bissau The Gambia Guinea Senegal HIV-2 Prevalence Highest in West Africa

Other Countries Reporting HIV-2 Infections < 1% HIV-2

HIV-2 – Transmission Same modes of transmission as HIV-1 -Male-to-male sexual contact (MSM) -Injection drug use (IDU) -Both MSM and IDU (MSM/IDU) -High-risk heterosexual contact* (HRH) -Other ' * Heterosexual contact with a person known to have or to be at high risk for HIV infection ‘ Includes persons that acquired HIV due to hemophilia or a blood transfusion and person whose risk factor was not reported or identified

HIV-2 – Clinical Aspects - Less transmissible - Progresses more slowly to AIDS - Lower mortality Source Marlink R., “Lessons learned from the second AIDS Virus, HIV-2”, AIDS 10:

HIV-2 – Risk Factors Native of West Africa Sexual contact or needle sharing with - a person from this endemic region - a person with known HIV-2 infection Children of women with or at-risk for HIV-2

Methods

HIV-2 – Surveillance Methods Laboratory component: Identify and confirm infections Interview component: Determine exposures, risk factors, and country of origin

CDC maintains supplemental database for reports on HIV-2 infection to ensure completeness of reporting Data Source

Diagnostic Criteria

Figure 1. Centers for Disease Control/Food and Drug Administration testing algorithm for use with combination HIV-1/HIV-2* enzyme immunoassays(EIAs) HIV-1/HIV-2 EIA HIV-1 Western PositiveNegative Indeterminate PositiveNegative Indeterminate Repeatedly Reactive HIV-2 Supplemental Test ( e.g., Western blot) Report as HIV positive ^ HIV-2 EIA * HIV- human immunodeficiency An Immunofluoresence assay (IFA) for HIV-1 antibodies has recently been licensed by the Food and Drug Administration and can be used instead of Western blot. Positive and negative IFA results should be interpreted in the same manner as similar results from Western blot tests. An indeterminate IFA should first be tested by Western blot and then as indicated by the Western blot results. ^ Perform HIV-2 EIA only if there is an identified risk factor for HIV-2 infection

HIV-2 – Laboratory Diagnosis 1.Screening HIV-1/2 ( EIA) 2. Perform HIV-1 Western Blot - Rule out HIV-1 first * 3. Bio-Rad HIV-1/ HIV-2 Multispot 4. Detect/Confirm HIV-2 antibodies - HIV-2 Western blot - PCR for unique sequences * HIV-2 antibodies can react with bands on HIV-1 not FDA licensed

Results

Distribution of HIV-2 cases in the U.S by Country of Birth, (N=68) West Africa 66% East Africa 11% India 12% Other Countries 2% West Africa 66% East Africa 11% Other Africa 7% India 12%

Distribution of HIV-2 cases among the different regions in the U.S, US regionNumber of cases Midwest26 (38%) South12 (18%) Northeast12 (18%) West8 (12%) Total68

Disease category of HIV-2 cases at diagnosis, United States, Among the 68 reported –19 cases had AIDS –29 cases did not have AIDS –20 cases did not have sufficient information to know status

Distribution of HIV-2 cases by Race/Ethnicity, United States, Race/EthnicityNumber of cases Blacks53 (77%) Asian /Pacific Islanders8 (12%) Other/unknown7 ( 10%) Total68

Discussion

HIV-2 infection continues to be of low prevalence in the U.S Majority of the cases reported are from persons of West African origin Diagnosis of HIV-2 continues to be a challenge – absence of FDA approved confirmatory test

Limitation Incomplete reporting since not all states have reported HIV-2 consistently to CDC? The total cases here may be an under estimation of the true cases

Conclusion Although HIV-2 continues to be of low prevalence in the US, monitoring the type of HIV infection needs to continue in the U.S –Since antiretroviral treatment (ARV) is different for HIV-2 infection –Misdiagnosis of HIV-2 to be HIV-1 due to cross- reactivity

Recommendation When HIV-2 is suspected, the following steps should be followed : Send specimens to CDC laboratory for confirmation Contact CDC coordinator for “Cases of Public Health Importance” (COPHI)

Questions ? Lata Kumar Tel: