Response to COVID-19 booster vaccinations in seronegative people with MS

Abstract

Importance: Uncertainties remain about the benefit of a 3rd COVID-19 vaccine for people with attenuated response to earlier vaccines. This is of particular relevance for people with multiple sclerosis (pwMS) treated with anti-CD20 therapies and fingolimod, who have substantially reduced antibody responses to initial vaccine course. Objective: To report humoral and T-cell responses following COVID-19 vaccine 3 in pwMS who were seronegative after COVID-19 vaccines 1&2. Design, setting and participants: PwMS taking part in a seroprevalence study without a detectable IgG response following COVID-19 vaccines 1&2 were invited to participate. Participants provided a dried blood spot +/- venous blood sample 2-12 weeks following COVID-19 vaccine 3. Data on demographics, MS treatment, and COVID-19 infection/vaccine dates were derived from the medical notes. Methods: Humoral and T cell responses to SARS-CoV-2 spike protein and nucleocapsid antigen were measured. The relationship between evidence of prior COVID-19 infection and immune response to COVID-19 vaccine 3 was evaluated using Fishers exact test. Results: Of 81 participants, 79 provided a dried blood spot sample, of whom 38 also provided a whole blood sample; 2 provided only whole blood. Anti-SARS-CoV-2-spike IgG seroconversion post-COVID-19 vaccine 3 occurred in 26/79 (33%) participants; 26/40 (65%) had positive T-cell responses. Overall, 31/40 (78%) demonstrated either humoral or cellular immune response post-COVID-19 vaccine 3. There no association between laboratory evidence of prior COVID-19 infection and anti-spike seroconversion following COVID-19 vaccine 3. Conclusions: Approximately one third of pwMS who were seronegative after initial COVID-19 vaccination seroconverted after booster (third) vaccination, supporting the use of boosters in this group. Almost 8 out of 10 had a measurable immune response following 3rd COVID-19 vaccine.