Case report of 5 Kaiser Permanente Northern California members diagnosed with CIS or RRMS with initial clinical relapse less than 2 weeks after a COVID19 mRNA vaccine

Introduction: Infections and immunizations have been identified as potential triggers for relapses of multiple sclerosis (MS). The various SARS Coronavirus 2 (COVID19) vaccine candidate clinical trials were not powered to detect whether these vaccines would trigger a relapse of MS. The Oxford/AstraZeneca COVID19 vaccine (AZD1222), approved abroad but not in the United States (US), did pause its phase 3 clinical trial in July 2020 for one patient diagnosed with MS shortly after receipt of the vaccine. To date, reports of clinically isolated syndrome (CIS) or relapsing remitting multiple sclerosis (RRMS) onset shortly after receipt of one of the mRNA vaccines, Pfizer- BioNTech (BNT162b2) or Moderna (mRNA1273), used in the US have not been publicized. Objectives: To describe the onset of CIS or RRMS in 5 Kaiser Permanente Northern California (KPNC) patients, all occurring within 2 weeks of receipt of a COVID-19 mRNA vaccine. Aims: To increase awareness that mRNA COVID19 vaccines may trigger MS relapses, possibly more likely in newly-diagnosed patients. Methods: All patients seen in the KPNC San Francisco (SF) regional MS clinic between January 2021 and mid-May 2021 were screened about timing and type of COVID19 vaccine exposure prior to their relapse. Approximately 5-10 new patients are seen in this clinic each week, about half of whom are newly diagnosed CIS or MS patients. Patients who had an initial clinical relapse within 2 weeks of receipt of a COVID19 vaccine were collected for inclusion in this case report. Results: Over the time period of the study, 5 patients receiving a diagnosis of CIS or RRMS (3 female, 2 male;ages 26-59) had received a mRNA COVID19 vaccine within 3-11 days of onset of neurological symptoms. Four of these relapses occurred after the second dose of the Pfizer-BioNTech vaccine, and 1 relapse occurred after the first dose of the Moderna vaccine. Four patients had a partial myelitis and one had a brainstem event. All patients had imaging findings suggestive of demyelinating disease, 3 with enhancing lesions. One case was seen in February 2021, one was seen in March 2021, and 3 were seen within a 1-week period in May 2021. Conclusions: A higher than average number of new CIS and RRMS diagnoses at KPNC SF's regional MS clinic in early 2021 have been time-correlated to receipt of a mRNA COVID19 vaccine, suggesting that these vaccines may increase the risk of a sentinel CNS demyelinating events in predisposed individuals.