People with rheumatoid arthritis who are currently taking biologic drugs may be safely vaccinated for the viral infection herpes zoster, according to new research findings. Herpes zoster occurs in one out of three U.S. adults during their lifetimes. A primary risk factor is age. People with RA are at as much as twofold increased risk of developing HZ due to their suppressed immune systems or taking medications like prednisone. Research has been mixed on the increased risk of HZ while taking methotrexate or anti-TNF biologic drugs.