HIV-2 Infection Surveillance -- United States, 1987-2009
July 29, 2011
The results of the analyses described in this report indicate that HIV-2 infections in the United States are rare, concentrated in the Northeast, and limited mainly to persons born in West Africa. Regional differences in the percentage of reported HIV cases caused by HIV-2 might be, in part, a result of the nonuniform geographic distribution of U.S. residents born in West Africa. New York is a major gateway for African immigrants to the United States.8
However, regional differences in the percentage of HIV cases caused by HIV-2 also could be the result of variations in completeness of diagnosis and reporting of HIV-2 by laboratories and state HIV surveillance programs. In particular, the large percentage of HIV-2 cases reported from New York City might have resulted, in part, from an increased focus on ascertainment of HIV-2 cases by the New York City Department of Health and Mental Hygiene, which has conducted active investigations to identify HIV-2 infections9 and issued an advisory to clinicians regarding diagnostic testing for HIV-2. The percentage of HIV-2 diagnoses based on an HIV-2 DNA test was several times higher among cases reported from New York City (68%), where many cases were diagnosed by the city's public health laboratory, than among cases from the four other regions (range: zero to 26%).
The findings in this report are subject to at least three limitations. First, the surveillance case definition for HIV infection and the working HIV-2 definition used in this analysis are intended primarily for analysis of epidemiologic trends and associations and might be inappropriate for other purposes, such as the clinical management of patients, which might require diagnostic considerations beyond the criteria used for the case definition. CDC currently is reviewing the HIV surveillance case definition to identify areas for revision, including the addition of specific criteria for HIV-2. Second, the 166 HIV-2 infections described in this report are likely an underestimate of HIV-2 cases in the United States. Many of the 76 suspected cases excluded from the analysis because of inadequate data on test results or missing identifiers might be actual HIV-2 cases. Other cases might not have been diagnosed because diagnostic tests specific for HIV-2 (e.g., DNA test or type-differentiating antibody immunoassay) were not widely used, and some cases might not have been recognized because of negative or persistently indeterminate results on assays designed primarily to detect HIV-1 antibodies. Finally, although 11% of HIV-2 cases had nucleic acid evidence of possible coinfection with HIV-1, the full extent of coinfection could not be assessed because HIV-1 nucleic acid test results were missing for 49% of the HIV-2 cases. In addition, 13 of the 17 detectable HIV-1 viral loads were <5,000 copies/mL, raising the possibility that they might be falsely positive.
Additional specific testing for HIV-2 should be considered if test results for HIV-1 are inconsistent with one another, inconclusive, or imply the absence of HIV infection despite clinical evidence suggesting its presence, particularly if the patient was born in or had other associations with areas such as West Africa, where HIV-2 infection is prevalent. Suspected HIV-2 cases should be reported to state or local health departments, which can conduct supplemental diagnostic tests for HIV-2 or arrange for them to be done at the CDC laboratory. In every state, confirmed HIV infection diagnoses are required by law or regulation to be reported to the health department.
This article was provided by U.S. Centers for Disease Control and Prevention. It is a part of the publication Morbidity and Mortality Weekly Report. Visit the CDC's website to find out more about their activities, publications and services.
Add Your Comment:
(Please note: Your name and comment will be public, and may even show up in
Internet search results. Be careful when providing personal information! Before
adding your comment, please read TheBody.com's Comment Policy.)