Vaccines and the Risk of Hospitalization for Multiple Sclerosis Flare-Ups.

Area of Science:

• Neurology
• Immunology
• Public Health

Background:

• Limited scientific data exists on the association between vaccination and multiple sclerosis (MS) exacerbations.
• Vaccination is critical for public health, necessitating clarity on its safety in MS patients.

Purpose of the Study:

• To investigate the risk of hospitalization for severe MS flare-ups following vaccination in individuals diagnosed with MS.

Main Methods:

• A nationwide cohort study in France analyzed data from the System of National Health Databases (2007-2017).
• A nested case-crossover analysis compared MS flare-up rates before and after vaccination (diphtheria, tetanus, poliomyelitis, pertussis, Haemophilus influenzae; influenza; pneumococcal).

Main Results:

• The study included 106,523 MS patients, with 35,265 hospitalized for flare-ups.
• No statistically significant association was found between vaccination and hospitalization for MS flare-ups (all vaccines: AOR 1.00; 95% CI, 0.92-1.09).
• Specific vaccines like DTPPHi (AOR 0.95) and influenza (AOR 0.98) showed no increased risk, while pneumococcal vaccine showed a borderline increased risk (AOR 1.20; 95% CI, 0.94-1.55).

Conclusions:

• This nationwide study in France found no evidence linking vaccination to an increased risk of MS flare-up hospitalizations.
• Further research is warranted to explore potential associations with different vaccine subtypes.