Breakthrough COVID-19 infection after vaccination in people with multiple sclerosis on disease modifying therapies in Latin America: data from RELACOEM registry

ABSTRACT

Introduction: In this study we aimed to monitor the risk of breakthrough COVID-19 infection in pwMS on different Disease Modifying Therapies (DMT) included in RELACOEM, a LATAM registry of MS and NMOSD patients infected with and vaccinated against COVID-19. Method(s) retrospective cohort study conducted between May 2021 and December 2021. The primary outcome was the appearance of infection during the follow-up time (at least three months after complete vaccination (second dose)). Specific information was requested (vaccine received, dose, date, symptoms, COVID- 19 infection, need for hospitalization, ventilatory assistance, treatment, and evolution). The primary objective of the analysis was to compare the incidence of breakthrough SARS-CoV-2 infections among the vaccinated pwMS in each DMT group. These conditions entail a PCR-confirmed test, and a time lag of at least 14 days from a full vaccination cycle (after the second vaccination dose). Cumulative incidence was reported by Kaplan Meier survival curves as well as incidence density. Result(s) A total of 857 pwMS patients from eight countries in LATAM were included. Mean age was 44.3 +/-12 years. The most frequent treatment used was fingolimod in 171 (19.9%). Most frequent first and second dose received was Astra-Zeneca (33%). During follow-up, a total of 28 COVID-19 cases were observed for a total exposure time of 150.965 days. The overall cumulative incidence was 3.2% (SE 0.22%) with an overall incidence density (ID) of 1.8 x 10.000 patients/day (95%CI 0.2-3.2). Compared to other DMTs, the incidence rate of breakthrough infections was significantly higher on ocrelizumab (6.02 (95%CI=5.65-7.16, RR=5.17 95%CI 3.27-7.12) and rituximab (6.94 (95%CI=6.15-9.12, RR= 5.93 95%CI 3.55-7.32) compared with other DMTs. No significant differences in the risk of breakthrough were observed for vaccine subtypes. Conclusion(s) An increased risk of breakthrough COVID-19 infections was observed in patients treated with ocrelizumab and rituximab.