Rabies vaccination and multiple sclerosis relapse: A retrospective cohort study

Risk of Relapse After COVID-19 Vaccination Among Patients With Multiple Sclerosis in France: A Self-Controlled Case Series

BACKGROUND AND OBJECTIVES

People with multiple sclerosis (MS) have an increased risk of severe coronavirus infection due to their level of motor disability or exposure to certain immunosuppressive treatments. Thus, patients with MS have had priority access to coronavirus disease 2019 (COVID-19) vaccination. However, relapses after vaccination have been reported, leading some patients to not seek the recommended booster doses. The main objective was to estimate the risk of severe relapse after 1, 2, and 3 (booster) doses of COVID-19 vaccination in patients with MS. The secondary objectives were to assess the risk of relapse in clinically meaningful subgroups according to the type of vaccine, the characteristics of the patients, and the use of disease-modifying treatments (DMTs).

METHODS

We conducted a nationwide study using data from the French National Health Data System. Patients with MS were identified according to ICD codes, specific treatments, and reimbursement data up to March 31, 2022. Relapses requiring treatment with high-dose corticosteroids were identified. A self-controlled case series method was used to evaluate the risk of relapse associated with COVID-19 vaccines in the 45 days after vaccination. The associated risk was evaluated after 1, 2, or 3 (booster) doses and is expressed as overall incidence rate ratios (IRRs) and in subgroups of interest.

RESULTS

Overall, 124,545 patients with MS were identified on January 1, 2021, and 82% received at least 1 dose of a COVID-19 vaccine (n = 102,524) until December 31, 2021, for a total of 259,880 doses. The combined IRR for MS relapse was 0.97 (0.91-1.03, p = 0.30). The same absence of risk was confirmed in various subgroups (age younger than 50 years, duration of MS < 10 years, use of DMT). A small increase in the relapse risk cannot be excluded after a booster dose (IRR 1.39 [1.08-1.80]) for patients with high MS activity, especially when not treated.

DISCUSSION

There is no increased risk of relapse requiring corticosteroid therapy after COVID-19 vaccination for almost all patients. We cannot exclude an increased risk after the booster dose for patients who have had at least 2 relapses in the previous 2 years.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that COVID-19 vaccination does not increase the risk of severe relapse in patients with MS.

Immunogenicity and safety of vaccines in multiple sclerosis: A systematic review and meta-analysis

BACKGROUND

Seroconversion rate of vaccines varies and requires further elucidation in patients with multiple sclerosis (MS) under treatment with disease-modifying therapies (DMTs). We aimed to investigate this in a systematic review and meta-analysis.

METHODS

MEDLINE(PubMed) and Cochrane databases were searched based on a pre-specified protocol (PROSPERO: CRD42020202018). Studies reporting on patients with MS, diagnosed with McDonald criteria getting vaccinated with any type of vaccine were included in the analysis. The primary endpoint was the incidence of patients being seropositive and experience adverse events after vaccination. Outcomes were expressed as proportions with respective 95% confidence interval (CI). Two reviewers independently screened and reviewed existing literature and assessed study quality with the Methodological index for non-randomized studies.

RESULTS

Of 295 articles, 45 studies were analyzed. Seroconversion after COVID-19 vaccines was 76% (95% CI, 70-80; I2 = 95%; 20 studies including 5601 patients. Protection was lower in patients treated with anti-CD20 antibodies and sphingosine-1-phosphate receptor (S1PR) modulators compared to untreated patients or treatment with other DMTs. Relapse occurred in 2% (95% CI, 1-3; I2 = 86%; 16 studies including 7235 patients). Seroconversion after seasonal influenza vaccines was 82% (95% CI, 65-91; I2 = 90%; 6 studies including 490 patients). Relapse rate was similar to this after COVID-19 vaccination.

CONCLUSION

The majority of MS patients vaccinated for COVID-19 or seasonal influenza mount an adequate immune response without safety concerns. Data on other vaccines are limited.

ECTRIMS/EAN consensus on vaccination in people with multiple sclerosis: Improving immunization strategies in the era of highly active immunotherapeutic drugs

BACKGROUND

With the new highly active drugs available for people with multiple sclerosis (pwMS), vaccination becomes an essential part of the risk management strategy.

OBJECTIVE

To develop a European evidence-based consensus for the vaccination strategy of pwMS who are candidates for disease-modifying therapies (DMTs).

METHODS

This work was conducted by a multidisciplinary working group using formal consensus methodology. Clinical questions (defined as population, interventions, and outcomes) considered all authorized DMTs and vaccines. A systematic literature search was conducted and quality of evidence was defined according to the Oxford Centre for Evidence-Based Medicine Levels of Evidence. The recommendations were formulated based on the quality of evidence and the risk-benefit balance.

RESULTS

Seven questions, encompassing vaccine safety, vaccine effectiveness, global vaccination strategy and vaccination in sub-populations (pediatric, pregnant women, elderly and international travelers) were considered. A narrative description of the evidence considering published studies, guidelines, and position statements is presented. A total of 53 recommendations were agreed by the working group after three rounds of consensus.

CONCLUSION

This first European consensus on vaccination in pwMS proposes the best vaccination strategy according to current evidence and expert knowledge, with the goal of homogenizing the immunization practices in pwMS.