The effect of live, attenuated measles vaccine and measles infection on measles antibody levels in serum and CSF of patients with multiple sclerosis or clinically isolated syndrome

High occurrence of measles, rubella and varicella zoster antibodies has been used as a biomarker for MS (the MRZ test). We analyzed measles antibody titres with respect to measles infection/measles vaccination status in 166 patients with MS or clinically isolated syndrome. Fifty blood donors served as controls. Measles vaccination yielded CSF measles antibodies in fewer patients (62%) than measles infection did (87%, p = 0.001) and yielded lower measles titres in both serum and CSF (p < 0.001). Controls had lower CSF measles titres than patients with measles vaccination alone (p < 0.001). Childhood vaccinations probably reduce the sensitivity of the MRZ diagnostic test for MS.