Safety of herpes zoster vaccination among inflammatory bowel disease patients being treated with anti-TNF medications

Background: The risk of herpes zoster (HZ) is elevated in inflammatory bowel disease (IBD) patients treated with anti-TNF medications. While it is optimal to give herpes zoster vaccine prior to initiation of therapy clinical circumstances may not always allow this. Aim: To determine the safety of giving herpes zoster vaccine while patients are on anti-TNF therapy. Methods: We conducted a retrospective cohort study involving IBD patients who were followed in the Veterans Affairs (VA) healthcare system between 2001 and 2016. Patients who received herpes zoster vaccine while on anti-TNF medication were identified through vaccination codes and confirmed through individual chart review. Our outcome of interest was development of HZ between 0 and 42 days after herpes zoster vaccine administration. Results: Fifty-six thousand four hundred and seventeen patients with IBD were followed in the VA healthcare system. A total of 59 individuals were on anti-TNF medication when they were given herpes zoster vaccine, and amongst them, 12 (20%) were also taking a thiopurine. Median age at the time of herpes zoster vaccine was 64.9 years and 95% of patients had a Charlson Comorbidity Index of >= 2. Median number of encounters within 42 days after receiving herpes zoster vaccine was two. No case of HZ was found within 0-42 days of HZV administration. Conclusion: Our data suggest that co-administering the herpes zoster vaccine to patients who are taking anti-TNF medications is relatively safe. This study significantly expands the evidence supporting the use of herpes zoster vaccine in this population, having included an elderly group of patients with a high Charlson Comorbidity Index who are likely at a much higher risk of developing HZ.