The risk of neurological diseases after COVID-19, influenza A/B or communityacquired pneumonia infection

ABSTRACT

Background and aims: Two years after onset of the pandemic, the precise nature and temporal evolution of the effects of COVID-19 on neurologic disorders remain uncharacterized. Studies have established an association with neurological syndromes, including anosmia, encephalopathy, and ischemic stroke, but it is unknown whether COVID-19 also influences the incidence of specific neurologic diseases and whether it differs from other respiratory infections. Methods: Using population-based electronic health records we investigated the association between COVID-19 and specific central and peripheral neurologic diseases. We compared patients with COVID-19 to individuals without, and to patients with influenza A/B and community-acquired bacterial pneumonia. We assessed the incidence of neurologic disease one, three, six, and twelve months after positive test results. Results: We identified 42,535 people with COVID-19, 8,329 with influenza, 1,566 with pneumonia, and 2,392,400 without COVID-19. Compared to individuals without COVID-19, patients with COVID-19 had increased relative risk (RR) of developing Guillain Barré syndrome (RR=3.1;95% CI=1.5-6.7), multiple sclerosis (RR=1.4;95% CI=1.2-1.7), narcolepsy (RR=3.2;95% CI=1.6-6.2), Parkinson's disease (RR=2.8;95% CI=2.4-3.2), Alzheimer's disease (RR=4.9;95% CI=4.0-6.0), dementia of any type (RR=5.2;95% CI=4.5-6.1), and ischemic stroke (RR=2.3;95% CI=2.1-2.5). However, compared to patients hospitalized with influenza, patients hospitalized with COVID-19 only had an increased risk of ischemic stroke at one (RR=1.9;95% CI=1.3-2.8), three (RR=1.8;95% CI=1.3-2.5) and six months (RR=1.9, 95% CI=1.3-2.7). Compared to patients hospitalized with pneumonia, the risk of neurologic diseases was not increased. Conclusion: COVID-19 increases the risk of a broad range of neurological disorders. However, except for ischemic stroke, there is no excess risk compared to influenza A/B and community-acquired pneumonia.