Vaccine hesitancy among people with multiple sclerosis

Background: The current severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) pandemic has raised awareness of vaccine hesitancy. Specific reasons for vaccine hesitancy among people with multiple sclerosis (pwMS) have not been fully described. Notably, pwMS may experience higher morbidity from vaccine-preventable diseases such as influenza, pneumococcal disease, and human papillomavirus (HPV)-associated warts and malignancies. Furthermore, screening for immunity against measles, mumps and rubella (MMR) is not standard practice, despite a resurgence of measles and mumps outbreaks in Europe and worldwide. We aimed to evaluate general vaccination status among pwMS to better inform vaccine practices in this cohort.

Methods: This was a prospective audit of pwMS attending an Irish tertiary referral MS centre. We designed a questionnaire that explored awareness, uptake, and hesitancy for the influenza, pneumococcal, SARS-CoV-2, HPV, and MMR vaccines. The clinician administered the questionnaire during the outpatient MS clinic.

Results: One-hundred-and-five pwMS participated in the audit, mean (SD) age 47.3 (12.8) years, mean MS disease duration 14.1 (9.5) years, median Expanded Disability Severity Scale (EDSS) score 2.0 (IQR 1.0-6.0), forty-nine (46.7%) were taking either maintenance immunosuppressive or immune reconstitution therapies. SARS-CoV-2 vaccine willingness among pwMS was higher (90.5 vs 60-80%) than that reported in other Western countries, and higher than that for the influenza and pneumococcal vaccines (∼80%) for which perceived unnecessity and unfamiliarity respectively were the main limiting factors. The primary reason for SARS-CoV-2 vaccine hesitancy was safety concern. PwMS who were explicitly advised by a healthcare professional to obtain the influenza vaccine were more likely to do so than those who were not (odds ratio, 8.1, 95% CI 2.8 - 23.4, p<0.001). Of pwMS currently receiving B-cell therapy (ocrelizumab/rituximab, n=12), all but one (n=11, 91.7%) have never received the pneumococcal vaccine, and a quarter (n=3) were uncertain whether to obtain this in the future. Patient-reported uptake of HPV (1.0%) and MMR (51.4%) vaccines were suboptimal. Prevalence of vaccine promotion among healthcare professionals was low (influenza vaccine, 4.8 - 32.4%; pneumococcal vaccine, 0 - 18.1%).

Conclusions: Vaccine hesitancy is common (10-20%) in pwMS, consequent to insufficient knowledge and misconceptions about vaccination among pwMS and suboptimal vaccine promotion by healthcare professionals who manage pwMS. Conscientious and context-specific vaccination counselling is necessary to tackle vaccine hesitancy among pwMS, including (i) avoiding infection-associated disability accrual during MS relapses, (ii) reducing the potentially higher risk of life-threatening/treatment-refractory complications that may be observed in those who develop vaccine-preventable infections while receiving certain DMTs, and (iii) avoiding attenuated vaccine responses or delayed/interrupted DMT with early pre-treatment vaccine delivery where possible.