Efficacy of Live Attenuated Herpes Zoster Vaccine in Patients With Inflammatory Bowel Diseases.

Background & Aims: The risk of herpes zoster virus infection is increased among patients with inflammatory bowel diseases (IBD). The herpes zoster vaccine (HZV) is therefore recommended for these patients, but little is known about its effectiveness, resulting in low use.

Methods: We conducted a retrospective cohort study using data from the national veterans Affairs Healthcare System (VAHS) from January 1, 2000 through June 30, 2016. We collected data from 39,983 veterans with IBD who had not received the HZV by an age of 60 years. The follow-up period started at age 60 or the date of first IBD medication prescription (whichever was later) and ended with the earliest diagnosis of herpes zoster infection, the end of the study period, or date of death. We identified veterans who received the HZV during the follow-up period and compared the incidence of herpes zoster between vaccinated vs unvaccinated patients. We performed multivariable Cox regression with time-dependent analysis to determine the risk of herpes zoster associated with vaccination status in the entire cohort and stratified by IBD medication.

Results: We identified 7170 patients who received the HZV during the follow-up period (17.9% of total cohort; 96.6% male and 94.2% Caucasian). The crude incidence rate of herpes zoster infection during the follow-up period for unvaccinated patients was 6.97/1000 person-years and for vaccinated patients was 4.09/1000 person-years. Vaccination was associated with significantly lower risk of herpes zoster infection, compared to lack of vaccination (adjusted hazard ratio, 0.54; 95% CI, 0.44 - 0.68).

Conclusion: Vaccination was associated with a significantly reduced risk of herpes zoster infection among veterans with IBD. This vaccine is therefore effective in patients with IBD, but underused.