For men with inflammatory bowel disease, herpes zoster vaccination was associated with about a 46% decrease in risk of associated infection, according to the results of a retrospective study from the national Veterans Affairs Healthcare System.
Crude rates of herpes zoster infection were 4.09 cases per 1,000 person-years among vaccinated patients versus 6.97 cases per 1,000 person-years among unvaccinated patients, for an adjusted hazard ratio of 0.54 (95% confidence interval, 0.44-0.68), reported Nabeel Khan, MD, of the University of Pennsylvania, Philadelphia, and associates. “This vaccine is therefore effective in patients with IBD, but underused,” they wrote in Clinical Gastroenterology and Hepatology.
Studies have linked IBD with a 1.2- to 1.8-fold increased risk of herpes zoster infection, the researchers noted. Relevant risk factors include older age, disease flare, recent use or high cumulative use of prednisone, and use of thiopurines, either alone or in combination with a tumor necrosis factor (TNF) inhibitor. Although the American College of Gastroenterology recommends that all patients with IBD receive the herpes zoster vaccine by age 50 years, the efficacy of the vaccine in these patients remains unclear.
For their study, Dr. Khan and associates analyzed International Classification of Diseases (ICD) codes and other medical record data from 39,983 veterans with IBD who had not received the herpes zoster vaccine by age 60 years. In all, 97% of patients were male, and 94% were white. Most patients had high rates of health care utilization: Approximately half visited VA clinics or hospitals at least 13 times per year, and another third made 6-12 annual visits.
Despite their many contacts with VA health care systems, only 7,170 (17.9%) patients received the herpes zoster vaccine during 2000-2016, the researchers found. Vaccination rates varied substantially by region – they were highest in the Midwest (35%) and North Atlantic states (29%) but reached only 9% in Montana, Utah, Wyoming, Colorado, Oklahoma, Texas, Arkansas, and Louisiana, collectively.
The crude rate of herpes zoster infection among unvaccinated patients with IBD resembled the incidence reported in prior studies, the researchers said. After researchers accounted for differences in geography, demographics, and health care utilization between vaccinated and unvaccinated veterans with IBD, they found that vaccination was associated with an approximately 46% decrease in the risk of herpes zoster infection.
Very few patients were vaccinated for herpes zoster while on a TNF inhibitor, precluding the ability to study this subgroup. However, the vaccine showed a protective effect (adjusted HR, 0.63) among patients who received thiopurines without a TNF inhibitor. This effect did not reach statistical significance, perhaps because of lack of power, the researchers noted. “Among the 315 patients who were [vaccinated while] on thiopurines, none developed a documented painful or painless vesicular rash within 42 days of herpes zoster vaccination,” they added. One patient developed a painful blister 20 days post vaccination without vesicles or long-term sequelae.
Pfizer provided funding. Dr. Khan disclosed research funding from Pfizer, Luitpold, and Takeda Pharmaceuticals. One coinvestigator disclosed ties to Pfizer, Gilead, Merck, AbbVie, Lilly, Janssen, Johnson & Johnson, UCB, and Nestle Health Science. The remaining researchers disclosed no conflicts.
SOURCE: Khan N et al. Clin Gastroenterol Hepatol. 2018 Oct 13. doi: 10.1016/j.cgh.2018.10.016.