 - Adolescents participating in PK part of the study may be enrolled without an active herpes labialis recurrence or with onset of signssymptoms of a recurrent herpes labialis episode longer than 24 hours before study drug administration, All adolescents participating in the pharmacokinetics assessments must fast for at least 8 hours prior to Visit 1 and be willing to fast for an additional 2 hours after study drug administration 