Rheumatologists should consider re-vaccinating their patients with herpes zoster vaccine at five years, say researchers who discovered protection wanes after this time.

The retrospective analysis of 130,107 Medicare patients with autoimmune diseases between 2006 and 2012 found rates of herpes zoster among vaccinated patients rose from 0.75 per 100 person-years during the first year after vaccination to 1.36 during the sixth year.

In an adjusted analysis, vaccinated patients had about half the risk of herpes zoster, compared with unvaccinated patients, during year 1 (relative risk, 0.52; 95% confidence interval, 0.45-0.61) and remained substantially less likely to develop shingles until year 6, when no significant protection against HZ was demonstrable (RR 0.92, CI: 0.45 – 1.86).

Meanwhile, another study presented at the conference found stroke risk was 50% higher in the month after patients with autoimmune diseases developed herpes zoster.

“These data provide urgency for developing strategies to reduce the risk of VZV  in vulnerable immunosuppressed patients” said lead author Dr Leonard Calabresi from the Cleveland Clinic Foundation.