Underestimation of HSV-2 Seroprevalence in a High-risk Population by Microneutralization Assay

Abstract

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. To determine the ability of CINA to identify HSV-2 antibodies alone or in the presence of HSV-1 antibodies. Sera from randomly selected women at the Seattle King County Sexually Transmitted Disease Clinic were tested by CINA and Western blot. 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. The seroprevalence of HSV-2 in an STD clinic population was seriously underestimated by CINA.