Incidence and risk factors for herpes zoster following heart transplantation

Data on the incidence, timing, and risk factors for herpes zoster (HZ) in heart transplant (HT) recipients are limited.

We determined HZ incidence rates and actuarial estimates of time to first HZ episode in 314 HT recipients at our institution from 1995 to 2010. We developed Cox models to assess potential risk factors for HZ in HT.

Median age at HT was 54 (range, 17-71) years; 237 (76%) were male. There were 60 episodes of HZ in 51 patients, with an overall incidence rate of 31.6 cases (95% confidence interval [CI], 23.5-41.6)/1000 person-years. Although most cases occurred during the first post-HT year, cumulative HZ incidence was 0.078 at 1, 0.15 at 5, and 0.20 at 10 years. Many patients had substantial HZ morbidity, including 14% with HZ ophthalmicus and 45% with post-herpetic neuralgia. Adjusting for age, gender, and acute cellular rejection episodes, exposure to mycophenolate mofetil (MMF) was an independent risk factor for HZ (adjusted hazard ratio [HR] 2.18; 95% CI, 1.20-3.96; P = 0.01), while ganciclovir-based cytomegalovirus prophylaxis reduced HZ risk (adjusted HR 0.09; 95% CI, 0.01-0.71; P = 0.02). Although age and female gender increased HZ risk, the magnitude of their effect was not statistically significant in Cox models.

HZ is common and morbid after HT, particularly with MMF exposure. Ganciclovir prophylaxis is effective in reducing the short-term risk of HZ, but the steady incidence of cases for years post HT makes long-term HZ prevention challenging. Augmenting varicella zoster virus immunity post HT with vaccines warrants further exploration.