Oral shedding of herpes simplex virus type 1 in immunocompetent persons

BACKGROUND: Reactivation of herpes simplex virus-1 (HSV-1) can result in recurrent herpes labialis lesions (RHL) and in oral shedding of virus. This study utilized polymerase chain reaction (PCR) to document the frequency and quantity of such shedding. METHODS: Thirty adults with greater than three RHL episodes per year were followed through one recurrence. They collected swabs for PCR every 12 h starting at prodrome and for 10 days thereafter. Shedding was analyzed with regard to frequency, timing and quantity. RESULTS: HSV-1 was detectable in 87% of participants for a mean of 4 days. Shedding occurred most frequently during the vesicle/ulcer stage (91% of subjects), but was common in both clinical and subclinical stages (50% vs. 23%, average log DNA copy number/ml(2) 2.6 vs. 1.4). CONCLUSION: The majority of RHL patients shed viral DNA. Shedding occurred before and after the appearance of clinical lesions. Such findings may be useful in designing methods to reduce viral shedding and prevent transmission.