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COVID-19 Breakthrough Infections Among Persons with Multiple Sclerosis Vaccinated Against Sars-Cov-2
Objectives: To describe the rate of severe breakthrough infections following SARS-CoV-2 vaccination among pwMS by DMT treatment.
Methods: The sample included all fully vaccinated pwMS in the deidentified Optum COVID EHR database (study period 12/11/19-12/9/21). The index date was 14 days after the last dose of the primary vaccine series. All pwMS who had COVID-19 prior to the index date or who had any non-OCR B-cell-depleting therapy, were pregnant, or had cancer during the study period were excluded. Included pwMS were categorized based on the last DMT used in the 6 months prior to the index date (i.e., index DMT) and pwMS without any DMT were classified as “no DMT recorded”. Severe breakthrough infections, including COVID-related hospitalizations, severe hospitalizations, and deaths, were described overall and by the index DMT. The data use agreement required that counts <10 were suppressed.
Results: A total of 3434 fully vaccinated pwMS were included in the study and 585 (17%) were treated with OCR, 238 (7%) with S1P receptor modulators, 33 (1%) with interferons (IFN), 1004 (29%) with other DMTs, and 1574 (46%) had no DMT recorded. Following vaccination, 21 (0.6%) pwMS had a COVID-related hospitalization and the number of hospitalizations was <10 in each DMT subgroup. Hospitalized pwMS tended to be older, covered by Medicare, and non-ambulatory compared with all pwMS. Most COVID-related hospitalizations were not severe (suppressed < 10) and there were no COVID-related deaths. Results will be updated to include outcomes during the Omicron wave.
Conclusions: COVID-related hospitalization and severe hospitalization following vaccination against SARS-CoV-2 were low among pwMS treated with OCR and other DMTs, and no COVID-related deaths were observed. Characteristics of pwMS who experienced a severe breakthrough event suggest similar risk factors as observed in the general population.