Two recent studies have reported that COVID boosters can increase the humoral response in MS patients during treatment with ocrelizumab or fingolimod. A number of studies have reported that these disease-modifying therapies (DMT) are associated with a blunted humoral response to COVID vaccination (Achiron et al. Ther Adv Neurol Disord 2021;14:17562864211012835. Gallo et al. Neurol Sci 2021;42:3523-3526).
An Italian MS centre study examined the humoral response in 47 MS patients treated with ocrelizumab or fingolimod (Capuano et al. J Neurol 2022;269:6185-6192). All subjects (mean age 42-46 years) received two doses of the Pfizer vaccine administered 21 days apart. The mean time from initial vaccination to the booster injection was 5 months. Prior to the booster, 42.9% of patients in the ocrelizumab group and 31.6% in the fingolimod were seropositive.
The seropositivity rate at 33.9 days post-booster was 57.14% for the ocrelizumab group and 84.2% for the fingolimod group. Anti-spike IgG titres were comparable in the two treatment groups; titres were significantly lower than those in healthy controls at all time points.
Following the booster shot, 25% of the DMT-treated patients contracted COVID-19; mean time to infection was 92 days after the booster. All COVID infections were mild. The anti-spike IgG response to infection was lower in patients on ocrelizumab (-53%) and fingolimod (-21%) compared to healthy controls.
A U.K. study analysed data for 79 MS patients who were seronegative following the initial vaccine series; 86% were receiving treatment with ocrelizumab or fingolimod (Upcott et al. ECTRIMS 2022; P343). The overall rate of seroconversion after a booster injection was 34%. Seroconversion rates were 17% of patients on ocrelizumab, 47% for those on fingolimod, and 100% for patients on all other DMTs. An additional 7% seroconverted after a second booster injection. There was an anti-CoV-2 T cell response in 65% of patients; a T cell response was not evident in fingolimod-treated patients.
The efficacy of the bivalent boosters has not been reported (Bivalent COVID booster approved in Canada, NeuroSens, September 16, 2022).