A study to determine whether vaccines, particularly those for hepatitis B (HepB) and human papillomavirus (HPV), increased the risk of multiple sclerosis (MS) or other acquired central nervous system demyelinating syndromes (CNS ADS) found no long-term association of vaccines with disease and a short-term increased risk in younger patients was likely resulted from existing disease, wrote authors Annette Langer-Gould, M.D., Ph.D., of Kaiser Permanente, Southern California, Pasadena, and colleagues.

Multiple Sclerosis symptoms/Mikael Häggström
Multiple Sclerosis symptoms/Mikael Häggström

The concern that vaccinations could prompt a small increase in the risk of MS and CNS ADS is controversial. Studies have had mixed results, with most showing no effect, and the studies have had limitations caused by small numbers of cases and other factors.

The authors examined the relationship between vaccines and MS or other CNS ADS by using data from Kaiser Permanente Southern California members. The authors identified 780 cases of CNS ADS and 3,885 control group patients; 92 cases and 459 control patients were females between the ages of 9 to 26 years, which is the indicated age range for HPV vaccination.

There were no associations between HepB vaccinations, HPV vaccination or any vaccination and the risk of MS or CNS ADS up to three years later. Vaccination of any type was associated with increased risk of a CNS ADS onset within the first 30 days after vaccination only in patients younger than 50 years but this association disappeared after 30 days. The authors said this may suggest that vaccines (like infections) may accelerate the transition from subclinical to overt autoimmunity in patients with preexisting disease. The authors say their results for HPV vaccinations are inconclusive because of the small number of cases and few previous studies in the topic.

“Our data do not support a causal link between current vaccines and the risk of MS or other CNS ADS. Our findings do not warrant any change in vaccine policy.”