Maternal Herpes simplex virus type 2 infection, syphilis and risk of intra-partum transmission of HIV-1: results of a case control study.
BACKGROUND
Genital ulcer disease including that caused by Herpes simplex virus type 2 (HSV-2) and syphilis facilitates sexual transmission of HIV-1. The effect of these infections on intra-partum mother-to-child-transmission (MTCT) of HIV-1 is unknown.


METHODS
A case-control study was conducted using archived sera from HIV-1 positive women enrolled in ZVITAMBO, an MTCT trial. Cases were 509 women who transmitted HIV-1 to their infants intra-partum; controls were 1018 women whose infants remained uninfected at 12 months. Maternal serum collected at delivery, were tested for HSV-2 antibody. The 6-week post-partum sample was also tested for syphilis by RPR and TPHA to identify women with incubating or active syphilis at delivery. Rates of prevalent and incident HSV-2 and recently acquired syphilis were compared between cases and controls.


RESULTS
Overall prevalence of maternal HSV-2 and active syphilis at delivery were 82.5% [95% confidence interval (CI), 80.6-84.5] and 4.0% (95% CI, 3.0-5.1), respectively. Prevalent HSV-2 was associated with increased intra-partum MTCT [adjusted odds ratio (OR), 1.50; 95% CI, 1.09-2.08]. The proportion of intra-partum transmissions potentially attributable to prevalent HSV-2 infection was 28.4% (95% CI, 7.3-44.7). Maternal infection with active syphilis at delivery was not associated with intra-partum MTCT (unadjusted OR, 0.89; 95%CI, 0.49-1.59; adjusted OR, 0.64; 95% CI, 0.34-1.20).


CONCLUSIONS
HSV-2 infection is common among HIV-1-positive women and is associated with an increased risk of intra-partum MTCT. More than 25% of intra-partum MTCT may be attributable to maternal HSV-2 co-infection. Active maternal syphilis at the time of delivery is not associated with intra-partum MTCT risk.
Cowan
Frances M
FM
Centre for Sexual Health and HIV Research, Royal Free and University College Medical School, University College London, UK.
Humphrey
Jean H
JH
Ntozini
Robert
R
Mutasa
Kuda
K
Morrow
Rhoda
R
Iliff
Peter
P
D000907:Antibodies, Bacterial / Q000097:blood*; D000914:Antibodies, Viral / Q000097:blood*; D016022:Case-Control Studies; D015897:Comorbidity; D005260:Female; D015658:HIV Infections / Q000453:epidemiology* / Q000635:transmission*; D015497:HIV-1; D006561:Herpes Simplex / Q000453:epidemiology*; D018258:Herpesvirus 2, Human / Q000276:immunology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology*; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D013587:Syphilis / Q000453:epidemiology*; D014210:Treponema pallidum / Q000276:immunology*; D015030:Zimbabwe / Q000453:epidemiology
D000907:Antibodies, Bacterial; D000914:Antibodies, Viral