The study of COVID-19 infection following vaccination in patients with multiple sclerosis

BACKGROUND: At this time vaccination against SARS-CoV2 is a global priority. Cases with multiple sclerosis (MS) were among the first vaccinated populations in Iran. We evaluated the change in the frequency of COVID-19 after vaccination and the associated factors with severe COVID-19 infection before and after full vaccination. METHODS: A questionnaire was validated to investigate the basic characteristics (age, gender, education, body mass index, smoking status, and comorbidities), MS disease and treatment status (MS type, MS duration, The Expanded Disability Status Scale (EDSS), disease modifying treatments) and the information about COVID-19 infection and severity. RESULTS: 692 (91.9%) of participants have received both doses of vaccines, of which Sinopharm appeared to be the most common type. Significant difference of COVID-19 infection prevalence was seen before vaccination and after full vaccination (difference: 0.16, 95% CI: 0.12–0.20) (p value < 0.001). The difference was not significant for severe cases (those who were admitted in the ward or ICU) relative to the COVID-19 cases or the whole participants. Of all the basic and disease factors, only EDSS showed a significant association with severe COVID-19 before vaccination. Severe COVID-19 in fully vaccinated cases did not show any significant relation to any of basic or disease characteristics except with prior history of severe allergic reactions (OR: 17.1, p value: 0.001). DISCUSSION: The decreased frequency of infection with SARS-CoV2 was predictable but the insignificant difference in cases with the severe forms of the disease raise concern. The only significant predictor was found to be severe allergic reactions. As there are debates on antiCD20 s association with severe COVID-19 and vaccine efficacy, we could not find such significant relation. The other noticeable point about the found relation of EDSS and critical COVID-19 before vaccination is the absence of such relation after full vaccination.