Serology results after COVID vaccine in multiple sclerosis patients treated with fingolimod

INTRODUCTION: While it is recommended that patients with multiple sclerosis (MS) be vaccinated against COVID-19, it is unknown what the vaccine response is in MS patients treated with fingolimod, an agent which modulates the humoral response. We aimed to characterize the immune response to the COVID-19 vaccine in MS patients treated with fingolimod and to explore which factors influenced response. METHOD: We collected the following data from 59 MS patients treated with fingolimod and vaccinated against COVID-19: age, sex, duration of treatment, number of vaccine doses, date of last vaccination, type of vaccine, lymphocyte count, history of COVID-19, and serology to measure the vaccine response. We used Student's t-test and Chi(2) test to see whether there was a relationship between these variables and seropositivity. A multivariate logistic regression model was used to identify factors influencing the serology result. A multivariate linear regression model was used to identify factors influencing the antibody titer. RESULTS: Twenty-eight participants (47%) developed a positive serology. Age (P < 0.001) and the duration of treatment (P = 0.002) were significantly related to seropositivity. Gender (P = 0.73), number of vaccinations (P = 0.78), lymphocyte count (P = 0.46), and the time between the last vaccine dose and blood sampling (P = 0.84) were not significant variables. Multivariate analysis using logistic regression (n = 59) showed that age (P = 0.003, RR = 2.28, 95%CI = 1.28, 4.07) and duration of treatment (P = 0.04, RR = 1.91, 95%CI = 1.04, 3.50) were significantly and independently correlated with COVID serology. Multivariate linear regression analysis of the antibody titer (n = 59) found the duration of treatment to be significant (P = 0.015), but not age (P = 0.53). After removing three outliers, age (P = 0.005, RR = 6.82, 95%CI = 1.66, 27.98) and duration of treatment (P = 0.008, RR = 5.12, 95%CI = 1.24, 21.03) were significantly correlated with the antibody titer. CONCLUSION: COVID-19 seropositivity was present in 47% of our sample of 59 MS patients on fingolimod. A strong relationship was found between antibody development, age, and duration of treatment, as well as between antibody titer and age and duration of treatment.