For each patient who is included, the study may last up to 22 weeks, including the screening and the follow-up period. During the study, subjects will come to the dermatology clinic up to 4 occasions: for a screening visit, Baseline visit, Day 42 as well as 84 days after they started taking the biological treatment for a last visit. If patients develop a varicella-like or shingles-like rash at any time after they received the vaccine, they will be requested to come back to the clinic within 72 hours of rash onset (preferably within 24 hours) for examination. Subjects will be asked to provide a lesion swab/vesicular fluid in this case.