Safety and seroconversion rates of mRNA and inactivated vaccines against SARS-CoV-2 among patients with multiple sclerosis: A multicentric observational study

ABSTRACT

Background: Vaccination strategies against SARS-CoV-2 have been implemented worldwide. Safety and effectiveness outcomes in special populations, such as MS patients receiving diseasemodifying therapy (DMT) may guide future recommendations. Objectives: To assess the safety and seroconversion (SC) rates of mRNA (Pfizer-BioNtech) and inactivated (Sinovac-CoronaVac) vaccines in patients with MS in Chile. Methods: Multicentric, prospective, observational study including patients from 4 tertiary centres. Humoral immune response was determined at least 4 weeks after the second dose of either vaccine, by assessing IgG against spike 1 (S1) and nucleocapsid (N) proteins (ECLIA Cobas, Roche) and events supposedly attributable to vaccination (AESAV) were collected. Subgroup comparisons according to DMT and type of vaccine were also performed. Results: A total of 115 patients were included (71% women, mean age 41+11 years, mean disease duration 8+6 years, 83% RRMS, median EDSS 2.0 (range 0-7.5)). Humoral immune response rates of the whole sample were 67% (100% for S1 and 16% for N). Thirty percent of the patients received mRNA vaccine, and SC was significantly higher in this group compared to the inactivated vaccine (81% vs. 61%, p=0.04). Interferon beta/ glatiramer acetate were used by 4% of the patients (100% SC), teriflunomide/dimethylfumarate 8% (100% SC), fingolimod 11% (92% SC), cladribine 7% (88% SC), natalizumab 6% (100% SC), ocrelizumab/rituximab 57% (45% SC, 58% with mRNA and 38% with inactivated vaccine), alemtuzumab 5% (100% SC), and 2% without DMT (100% SC). The most frequent AESAV were local pain (16%), myalgia (13%), headache (11%), and mild fever (3%). Two mild relapses with the inactivated vaccine were observed within the 8 weeks after the first dose. By the time of this report, 3 patients developed COVID- 19 after full vaccination (1 fingolimod, positive IgG-S1, mild COVID19;1 natalizumab, positive IgG-S1, mild COVID19;1 rituximab, negative IgG-S1, required hospitalization and 1 day of non-invasive mechanical ventilation). Conclusions: Vaccination with mRNA and inactivated vaccines appear to be safe in patients with MS, with less than 2% risk of relapse after vaccination. Higher seroconversion rates were observed using the mRNA vaccine. Humoral immune response rate is lower in patients using antiCD20. Determining cellular response and clinical effectiveness on preventing SARS-CoV-2 infection or severe COVID-19 is still needed to be determined.