Zoster vaccination didn't cause infection in patients on biologics

The herpes zoster vaccine reduced the incidence of herpes zoster infection in patients with immune-mediated disease, a new study found.

The vaccine is currently contraindicated in patients taking anti-tumor necrosis factor (TNF) therapies or other biologic drugs, due to concerns that it could increase the risk of infection. To investigate this assumption, researchers conducted a retrospective cohort study of more than 400,000 Medicare beneficiaries 60 and over who had been diagnosed with rheumatoid arthritis, psoriasis, psoriatic arthritis, ankylosing spondylitis or inflammatory bowel disease.

Between 2006 and 2009, 4% of the cohort patients received the zoster vaccine. Researchers followed the patients for an average of two years, but also focused specifically on the first 42 days after vaccination. During that initial period, the incidence of zoster infection was 7.8 per 1,000 patient-years (95% CI, 3.7 to 16.5 per 1,000 patient-years). In patients who weren't vaccinated, the overall zoster incidence rate was 11.6 per 1,000 patient-years (95% CI, 11.4 to 11.9 per 1,000 patient-years). About 600 of the vaccinated patients were taking biologics within 42 days of vaccination; none of them were found to develop zoster or varicella in that time. Overall, the researchers calculated a 39% reduced risk of zoster infection associated with vaccination over the two years (hazard ratio, 0.61; 95% CI, 0.52 to 0.71).

The study authors concluded that vaccination of patients with immune-mediated diseases may not be associated with any increased risk of zoster infection shortly after vaccination, and that a significant reduction in long-term risk of zoster infection from vaccination is also possible. They cautioned that the study was limited by the number of subjects and wide confidence intervals, so the finding of no infections in vaccinated patients' first 42 days should not be taken to mean that no risk is present.

Still, the results call into question the current contraindication against using the zoster vaccine in patients on biologics. The authors called for a randomized, controlled trial of these patients to further establish the safety and efficacy of zoster vaccination for them. The study was published in the July 4 Journal of the American Medical Association.