The severe COVID-19 outcomes seen in MS patients do not appear attributable to an inherent immune dysfunction or an impaired antiviral response, but rather to MS-related disability and morbidity. That is the conclusion of the Italian MuSC-19 Study Group in its analysis of COVID-19 in MS patients (Sormani et al. Neurol Neuroimmunol Neuroinflamm 2022;9:e1105).

A total of 1,362 MS patients with confirmed COVID-19 were included. Overall, the rates of hospitalization (12.8%), ICU admission (1.62%) and death (1.62%) were higher than in an age/sex-matched non-MS population (6.0%, 0.73% and 0.66%, respectively).

However, COVID-19 outcomes were similar in lower-risk MS patients (untreated and on most DMTs) and the population at large. Anti-CD20 therapy was associated with a higher risk of hospitalization (RR 3.03); patients on a beta-interferon had a lower risk of hospitalization.

Worse outcomes were largely confined to high-risk MS patients, defined as an EDSS score >3 and/or comorbidities. The relative risk of hospitalization, ICU admission or death was 2.85, 2.52 and 2.71, respectively, in high-risk MS patients compared to the general population. The relative risk was highest among patients treated with an anti-CD20 therapy (RR 4.27) or who were untreated (RR 3.13), and lower for patients on other DMTs (RR 2.31) or a beta-interferon (RR 1.80).

Excess deaths were mainly recorded in high-risk MS patients who were untreated (RR 3.26) or treated with an anti-CD20 agent (RR 5.40).