Background: Herpes simplex virus (HSV) remains latent in nerve root ganglia of infected persons and is thought to reactivate several times yearly. Recent in situ data show the localization of HSV-specific CD8(+) T cells at the dermal epidermal junction next to peripheral sensory nerve endings, suggesting that viral reactivation may occur more frequently than previously appreciated.
Methods: Twenty-five HSV-2-seropositive and 18 HSV-1-seropositive healthy adults collected anogenital and oral swabs, respectively, 4 times per day for 60 days. Swabs were assayed for HSV, using a quantitative polymerase chain reaction assay.
Results: Twenty-four percent of anogenital reactivations and 21% of oral reactivations lasted < or =6 h, and 49% of anogenital reactivations and 39% of oral reactivations lasted < or =12 h. Lesions were reported in only 3 (7%) of 44 anogenital reactivations and 1 (8%) of 13 oral reactivations lasting < or =12 h. The median HSV DNA levels at initial and last detection were 10(3.5) and 10(3.3) copies/mL, respectively, during anogenital reactivation and 10(3.7) and 10(3.0) copies/mL, respectively, during oral reactivation.
Conclusions: This high frequency of short subclinical HSV reactivation in immunocompetent hosts strongly suggests that the peripheral mucosal immune system plays a critical role in clearing HSV reactivations.