SARS-CoV-2 infection and risk of subsequent demyelinating diseases: national register-based cohort study.
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Montgomery S, Vingeliene S, Li H, Backman H, Udumyan R, Jendeberg J, Rasmussen G, Sundqvist M, Fall K, Hiyoshi A, Nyberg F
Brain Commun 6 (6) fcae406
[2024-11-29; online 2024-11-29]
Demyelinating diseases including multiple sclerosis are associated with prior infectious exposures, so we assessed whether SARS-CoV-2 infection is associated with subsequent diagnoses of non-multiple sclerosis demyelinating diseases and multiple sclerosis. All residents of Sweden aged 3-100 years were followed between 1 January 2020 and 30 November 2022, excluding those with demyelinating disease prior to 2020, comprising 9 959 818 individuals divided into uninfected and those who were infected were categorized into those with and without hospital admission for the infection as a marker of infection severity. Cox regression assessed the risk of two separate outcomes: hospital diagnosed non-multiple sclerosis demyelinating diseases of the CNS and multiple sclerosis. The exposures were modelled as time-varying covariates (uninfected, infection without hospital admission and infected with hospital admission). Hospital admission for COVID-19 was associated with raised risk of subsequent non-multiple sclerosis demyelinating disease, but only 12 individuals had this outcome among the exposed, and of those, 7 has an unspecified demyelinating disease diagnosis. Rates per 100 000 person-years (and 95% confidence intervals) were 3.8 (3.6-4.1) among those without a COVID-19 diagnosis and 9.0 (5.1-15.9) among those admitted to hospital for COVID-19, with an adjusted hazard ratio and (and 95% confidence interval) of 2.35 (1.32-4.18, P = 0.004). Equivalent associations with multiple sclerosis (28 individuals had this outcome among the exposed) were rates of 9.5 (9.1-9.9) and 21.0 (14.5-30.5) and an adjusted hazard ratio of 2.48 (1.70-3.61, P < 0.001). Only a small number of non-multiple sclerosis demyelinating disease diagnoses were associated with hospital admission for COVID-19, and while the number with multiple sclerosis was somewhat higher, longer duration of follow-up will assist in identifying whether the associations are causal or due to shared susceptibility or surveillance bias, as these diseases can have long asymptomatic and prodromal phases.
PubMed 39659973
DOI 10.1093/braincomms/fcae406
Crossref 10.1093/braincomms/fcae406
pmc: PMC11629974
pii: fcae406