Lower Risk of MS among People Living with HIV

Summary: A large, international population-based MS Canada-funded study found that individuals with human immunodeficiency virus (HIV) and those with HIV taking antiretroviral therapy (ART), had a significantly lower risk of MS compared to the general population. Infection by HIV and treatment with ART may be protective for MS. Further research on viruses will provide insights on the earliest factors involved in MS development and potential treatments for MS.

Background: There is growing evidence for the role of viruses in MS. For instance, Epstein-Barr virus (EBV) has emerged as a strong risk factor and early trigger of MS. Additionally, few observational studies noted that those with human immunodeficiency virus (HIV) may have significantly lower rates of MS compared to the general population.

Details: This study aimed to investigate the risk of MS in those living with HIV and those with HIV exposed to antiretroviral therapy (ART) compared to the general population.


  • The researchers examined a total of 29,163 people living with HIV in British Columbia, Canada and Sweden and assessed their health data using registries and administrative data.
  • Overall, they found that there were fewer cases of MS among HIV-positive individuals.
    • There were a total of 14 cases of MS in the HIV-positive individuals, instead of the expected 26 cases of MS.
    • Incidence of MS was 47% lower than expected in HIV-positive individuals.
    • Exposure to ART in people with HIV also showed lower rates of MS.

Impact: Infection with HIV or treatment with ART appears to be protective against the development of MS. However, we do not yet understand why this is the case. HIV results in the loss of immune cells called CD4+ T cells, and these cells have been linked with the development of MS. This protective effect however remains true even when people with HIV are exposed to ART, which is acting to suppress this virus. While unknown, ART may be acting to suppress other viruses, like EBV that are needed for MS development. Further research on viruses will shed light on the biological events that lead to MS and potential treatments.


McKay, K.A., Wijnands, J.M.A., Manouchehrinia, A., Zhu, F., Sereda, P., Li, J., Ye, M., Trigg, J., Kooij, K., Ekström, A.M., Gisslén, M., Hillert, J., Hogg, R.S., Tremlett, H. and Kingwell, E. (2023), Risk of Multiple Sclerosis in People Living with HIV: An International Cohort Study. Ann Neurol.  Link to article – here.

Additional Information:

  • Learn more about the MS Canada-funded study – here.
  • Read more from other sources: Tremlett’s MS Research Explained – here.