Impact of mass vaccination on SARS-CoV-2 infections among the total multiple sclerosis population receiving immunomodulatory disease-modifying therapies in England

Abstract:

This study aimed to understand changes in the risk of SARS-CoV-2 infection among all people with multiple sclerosis (MS) receiving immunomodulatory disease-modifying therapies (DMTs) in England, compared to the general population, following mass vaccination. Longitudinal data collected by the National Health Service (NHS) England on all MS DMT prescriptions and the UK Health Security Agency on all registered SARS-CoV-2 test results were analysed. The incidence rate ratio of SARS-CoV-2 infection among people with MS taking DMTs compared to the general population was calculated before (November 2020-January 2021) and after (July-August 2021) mass vaccination. Risk of SARS-CoV-2 infection among people on ocrelizumab or fingolimod compared to the general population increased following liberalisation of COVID-19 restrictions (during March-July 2021) despite mass vaccination. No changes were found with other DMTs. These findings converge with the impaired immune response to vaccines observed with ocrelizumab and fingolimod.