High Rate of β-Globin DNA Detection Validates Self-Sampling in Herpes Simplex Virus Shedding Studies

BACKGROUNDSelf-sampling is a convenient, feasible, and acceptable way of collecting genital specimens, but the veracity of reported self-collection is difficult to verify. We investigated whether a host gene, β-globin, can be used to confirm adequacy of self-collected mucosal and skin genital specimens in studies of genital herpes simplex virus type 2 (HSV-2) infection. METHODSHerpes simplex virus type 2–seropositive adults self-collected daily anogenital and oral swabs. Mucosal samples were tested for HSV DNA using a real-time quantitative polymerase chain reaction assay. A real-time Taqman polymerase chain reaction detecting the β-globin gene was used to quantify host cells. RESULTSOne hundred twelve participants collected 5559 genital and 2002 oral swabs. Sixty (54%) were women, 65% were HSV-2 seropositive, and 35% were HSV-1 and HSV-2 seropositive by Western blot. β-globin DNA was detected in 99% and 93% of swabs obtained from women and men, respectively. The quantity of β-globin DNA detected was significantly higher when HSV was present in genital swabs in women (0.1 log10 copies/mL; P = 0.001) and in men (0.6 log10 copies/mL; P < 0.001), but not in oral swabs in women (0.2 log10 copies/mL; P = 0.08) or men (0.0 log10 copies/mL; P = 0.70). CONCLUSIONSHuman β-globin DNA detection rate was high, and the quantity obtained significantly increased with genital, but not oral HSV shedding. The high rate of β-globin DNA detection is consistent with high adherence to study procedures in longitudinal studies of genital herpes shedding.