Surveillance for human immunodeficiency virus type 1 group O infections in the United States

Background: Reports that the human immunodeficiency virus type 1 (HIV-1) group O variants are not reliably detected by some commercial diagnostic tests have raised concerns about the sensitivity of existing screening tests, especially with regard to blood safety. Although it is unlikely that these divergent strains are prevalent in North America, systematic, continuous surveillance is needed to monitor the potential spread of HIV variants into that region, Study Design and Methods: Stored serum samples (n = 1072) from both high- and low-risk population groups al several sites in the United Stales and Puerto Rico were tested by peptide enzyme immunoassays specific for the prototypic HIV-1 group O strains, MVP5180 and ANT70. Results: None of the 1072 samples examined had peptide reactivity that was consistent with HIV-1 group O infection. Conclusion: While no evidence of specific HIV-I group O (MVP5180 or ANT70) infection was found in this study, the sensitivity of current tests has not been fully evaluated against the wide range of genetic variation of HIV. Therefore, it is important to continue active surveillance far HIV-1 and HIV type 2 strains, to characterize any divergent strains, and to judiciously modify tests to correct for any deficiencies in sensitivity.