A single-dose strategy for immunization with live attenuated vaccines is an effective option before treatment initiation in multiple sclerosis patients

Mumps-Measles-Rubella (MMR) and Varicella zoster vaccines (VAR) are live attenuated vaccines, usually administered in a two-dose scheme at least 4 weeks apart. However, single-dose immunization schemes may also be effective and can reduce delays in immunosuppressive treatment initiation in patients with multiple sclerosis (pwMS) who need to be immunized.To evaluate the immunogenicity of a single-dose attempt (SDA) versus the standard immunization scheme (SIS) with VAR and/or MMR in pwMS.Retrospective observational study in pwMS vaccinated against VAR and/or MMR. We compared seroprotection rates and antibody geometric mean titers (GMTs) between the two strategies.Ninety-six patients were included. Thirty-one patients received VAR and 67 MMR. In the SDA group, the seroprotection rate was 66.7% (95% confidence interval (CI): 53.3-78.3) versus 97.2% (95% CI: 85.5-99.9) in the SIS (p < 0.001). For the seroprotected patients, GMTs were similar for both schemes.An SDA of VAR and/or MMR vaccines could be sufficient to protect almost two-thirds of patients. Testing immunogenicity after a single dose of VZ and/or MMR could be included in routine clinical practice to achieve rapid immunization.