Evaluation of oral herpes simplex virus shedding among solid organ transplant recipients: A pilot study

Herpes simplex viruses (HSVs) frequently reactivate during immunosuppression and may be a risk factor for adverse outcomes after solid organ transplant (SOT). While suppressive antiviral therapy reduces the risk of symptomatic HSV reactivation, the kinetics of asymptomatic viral shedding with chronic immunosuppression after transplant are not well understood. We report the characteristics of oral HSV shedding among 15 HSV-1 seropositive SOT recipients (n = 8 liver, n = 7 kidney, median age 58.5 years, median 20 months post-transplant) who were not taking daily antiviral suppressive therapy.

Participants self-collected oral swabs three times daily for 6 weeks for HSV quantification and recorded the presence of oral symptoms or lesions in a diary.

Sample collection adherence was high (median 122 swabs/person, range: 85.7%-101.6% of expected swabs). Most participants (n = 12, 80%) experienced at least one shedding episode, with a median shedding rate of 8.9% (range: 0%-33.6%). There were 32 total shedding episodes, 24 (75%) of which occurred without symptoms or lesions. For episodes of known duration, the median length was 21.8 hrs (interquartile range: 10.8-46.1 hrs).

Most shedding episodes (78.1%) lasted >12 hrs, suggesting that twice-daily sampling may be sufficient to detect most episodes. These data show that self-collection of oral swabs is feasible for patients who have undergone SOTs and can provide insight into the frequency of oral HSV reactivation, which can be used to design future studies in this population.