biostudies-literatureUnknown20(11)Fisher SS<h4>Introduction</h4>Neurologic or immune-mediated conditions have been evaluated as potential adverse events (AEs) in coronavirus disease 2019 (COVID-19) vaccine safety surveillance. To contextualize United States (US) surveillance findings, it is important to quantify the association of AEs with COVID-19 diagnoses among US adults before the introduction of COVID-19 vaccines.<h4>Methods</h4>Cohort and self-controlled risk interval (SCRI) designs were used in 2 US administrative claims data sources-Merative™ MarketScan® Commercial Database (ages 18-64 years) and Medicare fee-for-service data (ages ≥ 65 years). AEs included Guillain-Barré syndrome (GBS), Bell's palsy, encephalitis/encephalomyelitis, narcolepsy, immune thrombocytopenia (ITP), and transverse myelitis. The cohort (study period, 1 April 2020-10 December 2020) included adults with COVID-19 diagnoses and matched comparators. Inverse probability of treatment-weighted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated. The SCRI (study period, 1 June 2020-10 December 2020) identified the AEs in risk windows after COVID-19 diagnosis and pre- and postexposure reference windows. Relative incidences (RIs) and 95% CIs were estimated with seasonality-adjusted conditional Poisson regression models accounting for outcome-dependent observation windows.<h4>Results</h4>The study observed a consistent association between COVID-19 diagnosis and GBS: MarketScan HR = 9.57 (95% CI, 1.23-74.74), RI = 8.53 (95% CI, 2.45-29.7); Medicare HR = 1.97 (95% CI, 1.04-3.74), RI = 4.63 (95% CI, 1.78-12.01). For ITP, the association was weaker, but still consistently elevated: MarketScan HR = 2.06 (95% CI, 1.20-3.53), RI = 1.74 (95% CI, 1.01-3.00); Medicare HR = 1.36 (95% CI, 1.18-1.57), RI = 1.91 (95% CI, 1.60-2.28). For all remaining AEs, there was not consistent evidence of an association with COVID-19, with estimates that were generally modest, imprecise, or varying by study design.<h4>Conclusions</h4>COVID-19 diagnoses were associated with an increased risk of GBS and ITP in both data sources and study designs. Increased risks of other neurologic/immune-mediated AEs cannot be ruled out.PloS onee0333704https://www.ebi.ac.uk/biostudies/studies/S-EPMC12643290biostudies-literatureRisk of neurologic or immune-mediated adverse events after COVID-19 diagnosis in the United States.PMC12643290Anthony MSBui CFisher SSLindaas ALloyd PCClarke TCAnderson SADuenas PFKowarski LSChillarige YMuthuri SGGruber JFShoaibi ACheng ASBeers JSheng MLyu HBurrell TForshee RAChen YLayton JBRichey MMMcKillop MMfalseRisk of neurologic or immune-mediated adverse events after COVID-19 diagnosis in the United States.<h4>Introduction</h4>Neurologic or immune-mediated conditions have been evaluated as potential adverse events (AEs) in coronavirus disease 2019 (COVID-19) vaccine safety surveillance. To contextualize United States (US) surveillance findings, it is important to quantify the association of AEs with COVID-19 diagnoses among US adults before the introduction of COVID-19 vaccines.<h4>Methods</h4>Cohort and self-controlled risk interval (SCRI) designs were used in 2 US administrative claims data sources-Merative™ MarketScan® Commercial Database (ages 18-64 years) and Medicare fee-for-service data (ages ≥ 65 years). AEs included Guillain-Barré syndrome (GBS), Bell's palsy, encephalitis/encephalomyelitis, narcolepsy, immune thrombocytopenia (ITP), and transverse myelitis. The cohort (study period, 1 April 2020-10 December 2020) included adults with COVID-19 diagnoses and matched comparators. Inverse probability of treatment-weighted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated. The SCRI (study period, 1 June 2020-10 December 2020) identified the AEs in risk windows after COVID-19 diagnosis and pre- and postexposure reference windows. Relative incidences (RIs) and 95% CIs were estimated with seasonality-adjusted conditional Poisson regression models accounting for outcome-dependent observation windows.<h4>Results</h4>The study observed a consistent association between COVID-19 diagnosis and GBS: MarketScan HR = 9.57 (95% CI, 1.23-74.74), RI = 8.53 (95% CI, 2.45-29.7); Medicare HR = 1.97 (95% CI, 1.04-3.74), RI = 4.63 (95% CI, 1.78-12.01). For ITP, the association was weaker, but still consistently elevated: MarketScan HR = 2.06 (95% CI, 1.20-3.53), RI = 1.74 (95% CI, 1.01-3.00); Medicare HR = 1.36 (95% CI, 1.18-1.57), RI = 1.91 (95% CI, 1.60-2.28). For all remaining AEs, there was not consistent evidence of an association with COVID-19, with estimates that were generally modest, imprecise, or varying by study design.<h4>Conclusions</h4>COVID-19 diagnoses were associated with an increased risk of GBS and ITP in both data sources and study designs. Increased risks of other neurologic/immune-mediated AEs cannot be ruled out.2025-01-01T00:00:00Z20252026-06-05T16:54:25.899Z2026-06-05T03:06:34.11ZS-EPMC126432904128464910.1371/journal.pone.0333704