A Study to Assess Immune Response Following Zoster Vaccination to Subjects With Rheumatoid Arthritis Receiving Tofacitinib or Placebo With Background Methotrexate

Inclusion Criteria: * Subjects must have moderate to severe rheumatoid arthritis inadequately controlled by methotrexate as defined by the American College of Rheumatology (ACR) classification criteria for Rheumatoid arthritis, painful and swollen joint counts and C-reactive protein (CRP). * Screening CRP \>3 mg/L or CDAI score \> 10 at screening or at baseline before vaccination. * Subjects must have active disease at screening and baseline. * Must be at least 50 years of age or older. Exclusion Criteria: * History of receiving any varicella-zoster virus vaccine * Receipt of any vaccines within 6 weeks of first dose of study treatment. * Subjects with current infections or history of infections. * History of recurrent (more than one episode) of herpes zoster or disseminated (a single episode) of herpes zoster or disseminated (a single episode) of herpes simplex.