Adults diagnosed with Multiple Sclerosis or Neuromyelitis optica spectrum disease and receiving an anti‑CD20 antibody called rituximab every six months are eligible for the trial, which evaluates the use of the subunit shingles vaccine Shingrix that protects against the virus that causes shingles.
The purpose of the study is to compare two different timing schedules for giving the vaccine in order to determine which schedule leads to a stronger antibody (immune‑system protein) response. In the standard schedule, the second vaccine dose is given two months after the first; in the experimental schedule, the second dose is given six months after the first.
Participants receive the first vaccine dose one month before their scheduled rituximab infusion, followed by the second dose either two months or six months later, depending on the assigned group. Blood samples are taken before the first dose, one month after the second dose, and at later visits to measure antibody levels and monitor any side effects. The study continues for about a year with regular clinic visits for safety checks.
France 
