Comparison of focus HerpesSelect and Kalon HSV-2 gG2 ELISA serological assays to detect herpes simplex virus type 2 antibodies in a South African population.
BACKGROUND
Sero-epidemiological studies of herpes simplex virus (HSV) type 2 infection in Africa remain difficult to interpret as a result of the high rate of false-positive results observed when using the new recombinant gG2 HSV-2 ELISA tests. The performance of two widely used gG2 ELISA was compared to derive an appropriate testing algorithm for use in South Africa.


METHODS
Sera from 210 women attending family planning clinics in Johannesburg were tested using HerpeSelect and Kalon HSV-2 gG2 assays. Sera from 20 discordant pairs, 44 concordant positive and 33 concordant negative samples were further tested by HSV Western blot. The sensitivity and specificity of each test and of combination algorithms compared with Western blot were calculated.


RESULTS
HerpeSelect had a sensitivity of 98% (95% CI 95 to 100) and specificity of 61% (95% CI 48 to 74). Kalon was less sensitive (89%, 95% CI 83 to 94) but more specific (85%, 95% CI 61 to 100). Seroprevalence may have been overestimated by as much as 14% by HerpeSelect. Specificity was improved by raising the cut-off index for the determination of a positive result for HerpeSelect (to >or=3.5), but not for Kalon. HIV-1 infection reduced the specificity of HerpeSelect to 30%. Improved sensitivity and specificity were obtained by a two-test algorithm using HerpeSelect (>or=3.5) as the first test and Kalon to resolve equivocal results (sensitivity 92%, 95% CI 82 to 98; specificity 91%, 95% CI 79 to 98).


CONCLUSIONS
Newer HSV-2 serological tests have low specificity in this South African population with a high HIV-1 prevalence. Two-step testing strategies could provide rational testing alternatives to Western blot.
Delany-Moretlwe
Sinéad
S
Reproductive Health and HIV Research Unit, University of the Witwatersrand, PO Box 18512, Hillbrow, Johannesburg 2038, South Africa. sdelany@rhru.co.za
Jentsch
Ute
U
Weiss
Helen
H
Moyes
Jocelyn
J
Ashley-Morrow
Rhoda
R
Stevens
Wendy
W
Mayaud
Philippe
P
D000293:Adolescent; D000328:Adult; D000465:Algorithms; D000914:Antibodies, Viral / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D015658:HIV Infections / Q000150:complications / Q000453:epidemiology; D015497:HIV-1; D006558:Herpes Genitalis / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology*; D018258:Herpesvirus 2, Human / Q000276:immunology*; D006801:Humans; D008875:Middle Aged; D012680:Sensitivity and Specificity; D016036:Seroepidemiologic Studies; D013019:South Africa / Q000453:epidemiology; D055815:Young Adult
D000914:Antibodies, Viral