The Radiologically Isolated Syndrome (RIS) is defined as incidental Magnetic Resonance Imaging (MRI) abnormalities fulfil the criteria for dissemination in space, suggestive of multiple sclerosis. Nowadays, mandatory vaccination in patients with multiple sclerosis (MS) is widely recommended. Regarding COVID19, the absence of specific warnings led to the proposal of vaccination in patients with inflammatory diseases of the central nervous system. We aimed to evaluate if COVID19 vaccination or infection increased the risk of clinical conversion to multiple sclerosis or evidence of disease activity (EDA) in a cohort of RIS subjects.

Inclusion Criteria:

• patients belong to the RISC cohort;
• totally vaccinated ou partially vaccinated patient
• vaccination status known

Exclusion Criteria:

• presented a first clinical event before the COVID19 vaccination

Patients fulfilling the Radiologic Isolated Syndrome criteria