Herpes Zoster Incidence High In Solid Organ Transplant Recipients

The incidence is highest among African Americans, heart recipients, and older subjects.

The study, led by Steven A. Pergam, MD, MPH, of Fred Hutchinson Cancer Center in Seattle, included a multicenter cohort of 1,077 patients who received an SOT from January 1995 through December 2007 and follow-up care at a Veteran's Affairs hospital. The group included 500 kidney, 461 liver, and 80 heart transplant patients. Thirty-six patients received other organs.

The overall HZ incidence was 22.2 infections per 1,000 patient-years, according to a report in Transplant Infectious Disease (published online ahead of print). The incidence was 37.6 per 1,000 patient-years among African-American subjects. By comparison, the annual incidence in the general population is estimated to be 1.5-3.0 cases per 1,000 person-years.

Compared with white subjects, African Americans had a nearly twofold increased risk, the researchers reported.

Heart transplant recipients had the highest incidence of HZ—40.0 infections per 1,000 patient-years. Compared with kidney transplant recipients, heart transplant recipients had a 70% increased risk of HZ infection after adjusting for multiple potential confounders.

“To the best of our knowledge, this study is one of the largest multicenter cohort of SOT recipients to date to assess the incidence of HZ,” the authors noted. “These data provide important information on long-term risk of HZ following SOT, afford the first assessment of risk in other non-white populations, and present further evidence for an increased risk of HZ in SOT recipients.”

Dr. Pergam and his colleagues also pointed out that their study is the first to reveal a higher incidence of HZ in African-American SOT recipients. This higher incidence could be related to higher rates of organ rejection in this racial group, increased utilization of VA resources, differences in immunosuppressive regimens, or some other undetermined racial variations in viral immune response.

The incidence of HZ declined with time. Subjects who received their organ from 1996-1999, 2000-2004, and 2005-2007 had an incidence of 29.0, 19.1, and 15.2 per 1,000 patient-years, respectively.

The researchers hypothesize that the decreased incidence observed in latter cohorts is likely in part a result of shorter follow-up and increasing use of antiviral cytomegalovirus prophylaxis, which has been shown to further limit HZ risk.

Similar to the general population, the incidence was also highest among patients older than 55 years: 26.3 per 1,000 patient-years. By comparison, the incidence was 20.4 and 19.8 per 1,000 patient-years for patients younger than 45 and those aged 45-55 years.