RESUMO
BackgroundPatients with Multiple Sclerosis (pwMS) treated with anti-CD20 or fingolimod showed a reduced humoral response to SARS-CoV-2 vaccines. In this study we aimed to monitor the risk of breakthrough SARS-CoV-2 infection in pwMS on different Disease Modifying Therapy (DMT). MethodsData on number of vaccinated patients and of patients with a breakthrough infection were retrospectively collected in 27 Italian MS centers. We estimated the rate of breakthrough infections and of infection requiring hospitalization per DMT. Findings19641 vaccinated pwMS were included in the database. After a median follow-up of 8 months, we observed 137 breakthrough infections. As compared to the other DMTs, the rate of breakthrough infections was significantly higher on ocrelizumab (0.57% vs 2.00%, RR=3.55,95%CI=2.74-4.58, p<0.001) and fingolimod (0.58% vs 1.62%, RR=2.65,95%CI=1.75-4.00, p<0.001), while there were no significant differences in any other DMT group. In the ocrelizumab group the hospitalization rate was 16.7% vs 19.4% in the pre-vaccination era (RR=0.86,p=0.74) and it was 3.9% in all the other DMT groups vs 11.9% in the pre-vaccination period (RR=0.33,p=0.02). InterpretationThe risk of breakthrough SARS-CoV-2 infections is higher in patients treated with ocrelizumab and fingolimod, and the rate of severe infections was significantly reduced in all the DMTs excluding ocrelizumab.
RESUMO
BackgroundPatients with Multiple Sclerosis (pwMS) treated with anti-CD20 or fingolimod showed a reduced humoral response to mRNA-based SARS-CoV-2 vaccines, while the degree of such responses is unimpaired and similar in pwMS treated with other disease modifying therapies (DMTs), or untreated. However, the nature of the SARS-CoV-2 vaccine-induced immune response is based also on cellular immunity and there is emerging evidence that anti-SARS-CoV-2 specific CD4 and CD8 T cell responses can be detected after vaccination also in patients with low antibody levels. In this study we aimed to monitor the risk of breakthrough SARS-CoV-2 infection and to identify correlates of reduced protection in frail vaccinated pwMS on different DMTs. MethodsWe designed a long term clinical follow-up of the CovaXiMS (Covid-19 vaccine in Multiple Sclerosis), a prospective multicenter cohort study enrolling pwMS scheduled for SARS-CoV-2 vaccination with mRNA vaccines and tested for SARS-CoV-2 antibodies before and after the second vaccine dose. These patients were followed with periodic phone calls up to a mean time of 6 months, and all the SARS-CoV-2 breakthrough infections were registered. The impact of DMTs on cumulative incidence of breakthrough Covid-19 cases was presented by Kaplan-Meier curves. A multivariable logistic model was run to assess factors associated to a higher risk of breakthrough infections. Findings1705 pwMS (81.6% BNT162b2 and 18.4% mRNA-1273) had a full vaccination cycle (2 vaccine doses, 21/28 days apart). Of them, 1509 (88.5%) had blood assessment 4 weeks after the second vaccine dose. During follow-up, 23 breakthrough Covid-19 infections (cumulative incidence: 1.5%, SE=0.3%) were detected after a mean of 108 days after the second dose (range, 18-230). Of them, 9 were on ocrelizumab, one on rituximab, 4 on fingolimod, 6 on dimethyl-fumarate, one on teriflunomide, and 2 were untreated. Just two cases (a woman on ocrelizumab and a man on teriflunomide) required hospitalization. The probability to be infected was associated only with SARS-CoV-2 antibody levels measured after 4 weeks from the second vaccine dose (HR=0.63, p=0.007); an antibody level of 660 U/mL was calculated as the cutoff for higher risk of infection. InterpretationOur data show that the risk of breakthrough SARS-CoV-2 infections is mainly associated with reduced levels of the virus-specific humoral immune response. FundingFISM [2021/Special-Multi/001]; the Italian Ministry of Health grant Progetto Z844A 5x1000. Italian Ministry of Health: Ricerca Corrente to IRCCS Ospedale Policlinico San Martino.
