A new study suggests COVID-19 may be a risk factor for multiple sclerosis. Researchers report a raised risk of MS among people who had severe COVID-19. However, only an extremely small number of people who had severe COVID-19 received a subsequent MS diagnosis.

Researchers at Örebro University and Örebro University Hospital, Sweden, examined the records of all patients with COVID-19 that were admitted to a hospital in Sweden between 2020 and 2022. The results showed nearly 26 per 100,000 patients with serious COVID-19 subsequently developed MS. This was more than double the risk than in those without a COVID-19 diagnosis.

The study’s authors noted that MS is an uncommon disease and very few people in the study had an MS diagnosis linked with COVID-19. Approximately 26 people with new-onset MS per 100,000 with serious COVID-19 is only 0.02 percent.

Researchers suspect the number who are diagnosed with MS following severe COVID-19 will increase over the years following the pandemic. They said it can take up to 10 to 20 years until an MS diagnosis following a relevant exposure to the brain or spinal cord. The extent to which serious COVID-19 is a cause of MS will become clearer in several years.

The study’s authors hope the research will result in earlier diagnosis of MS among those affected so they can be treated before development of more advanced disease.

They noted the majority of people who were infected with COVID-19 will not develop diseases such as MS and they should not worry. However, people with symptoms should seek medical advice. The earlier patients with MS are treated, the better quality of life they will have, because treatments delay the worsening of the disease.

They also emphasized the importance of ensuring that everyone is up to date with their vaccinations to prevent infections.

The research is published in the journal Brain Communications.