UNDERESTIMATION OF HSV-2 SEROPREVALENCE IN A HIGH-RISK POPULATION BY MICRONEUTRALIZATION ASSAY

Background: Complement independent neutralizing antibody assays (CINA) have been used in seroepidemiologic studies and in diagnostic laboratories to distinguish between antibodies to herpes simplex virus types 1 (HSV-1) and 2 (HSV-2). The accuracy of CINA has not been rigorously tested against protein-specific typing assays, such as Western blot. Goal of this Study: To determine the ability of CINA to identify HSV-2 antibodies alone or in the presence of HSV-1 antibodies. Study Design: Sera from randomly selected women at the Seattle King County Sexually Transmitted Disease Clinic were tested by CINA and Western blot. Results: Of 521 women tested, 81% had HSV antibodies by Western blot and 76% had neutralizing antibodies. Of 220 sera with HSV-2 antibodies by Western blot, 106 (48%) were serotyped correctly by CINA. Of the women studied, 140 (27%) had type-indeterminate neutralizing antibodies; 55 of these sera (39%) had antibody only to HSV-1 by Western blot. Conclusion: The seroprevalence of HSV-2 in an STD clinic population was seriously underestimated by CINA.