The risk of TB and hepatitis B virus (HBV) appears to be no greater with TOF than with bDMARDs. Most cases of TB during TOF studies occurred in regions with high background rate of TB, including east Asian countries. TOF is also associated with a higher rate of herpes zoster (HZ) compared with bDMARDs. DMARDs used to treat RA can increase the risk of infections by causing a degree of immunosuppression. A range of bacterial and viral infections have been observed in association with DMARD therapy...