Increased Autoimmune Disorder Risk From COVID-19 Is Reduced With Vaccinations

Although COVID-19 is associated with an increased risk for new onset of multiple autoimmune disorders (ADs), this risk is reduced with full COVID-19 vaccination, researchers reported in eClinicalMedicine.

The retrospective cohort study examined the effect of SARS-CoV-2 infection and COVID-19 vaccination on newly diagnosed ADs with use of electronic medical records from the Hong Kong Hospital Authority.

The cohort was classified into a COVID-19 group and non-COVID group based on diagnostic COVID-19 test results from April 1, 2020, to November 15, 2022. COVID-19 diagnosis was confirmed by positive polymerase chain reaction or positive rapid antigen test.

Adults with full COVID-19 vaccination (≥2 doses) were compared with partially/nonvaccinated individuals (1/0 dose). All participants were followed up from the study index date until death, the occurrence of incident ADs, or study end date, whichever occurred first. Outcomes were incident ADs diagnosed in inpatient and outpatient settings.

The analysis included 1,028,721 patients with COVID-19 (mean age, 52.68 years; 55% female) and 3,168,467 control individuals without COVID-19 (mean age, 54.09 years; 56% female). Crude incidence rates for ADs varied widely: incidence rates for other (ie, non-rheumatoid) autoimmune arthritis were 19.83 in the COVID-19 group vs 14.92 in the control group per 10,000-person years; for alopecia areata, incidence rates were 0.02 in the COVID-19 group vs 0.05 in the control group per 10,000-person years.

Researchers found that individuals with COVID-19 infection vs those without had a higher risk for the following new-onset ADs:

• pernicious anemia (adjusted hazard ratio [aHR], 1.72; 95% CI, 1.12-2.64);
• spondyloarthritis (aHR, 1.32; 95% CI, 1.03-1.69);
• rheumatoid arthritis (aHR, 1.29; 95% CI, 1.09-1.54);
• other autoimmune arthritis (aHR, 1.43; 95% CI, 1.33-1.54);
• psoriasis (aHR, 1.42; 95% CI, 1.13-1.78);
• pemphigoid (aHR, 2.39; 95% CI, 1.83-3.11);
• Graves’ disease (aHR, 1.30; 95% CI, 1.10-1.54);
• anti-phospholipid antibody syndrome (aHR, 2.12; 95% CI, 1.47-3.05);
• immune-mediated thrombocytopenia (aHR, 2.1; 95% CI, 1.82-2.43);
• multiple sclerosis (aHR, 2.66; 95% CI, 1.17-6.05); and
• vasculitis (aHR, 1.46; 95% CI, 1.04-2.04).

COVID-19-vaccinated patients had a decreased risk for other autoimmune arthritis (aHR, 0.74; 95% CI, 0.65-0.84), pemphigoid (aHR, 0.45; 95% CI, 0.29-0.70), immune-mediated thrombocytopenia (aHR, 0.41; 95% CI, 0.33-0.52), Graves’ disease (aHR, 0.58; 95% CI, 0.43-0.77), anti-phospholipid antibody syndrome (aHR, 0.55; 95% CI, 0.31-0.99), and systemic lupus erythematosus (SLE) (aHR, 0.29; 95% CI, 0.18-0.47) vs COVID-unvaccinated patients.

Limitations include the potential for under-reporting of COVID-19 cases and limited generalizability of the findings (ie, to autoimmune-naïve individuals only). Also, only a selected subset of autoimmune diseases was included, and socio-economic confounders such as income, access to health care, and education were not evaluated.

“Physicians should be aware of the possible connections between SARS-CoV-2 and autoimmune manifestations to optimize disease management procedures, early detection, and intervention in light of the ongoing pandemic,” stated the investigators. “Future studies investigating pathology and mechanisms would be valuable to interpreting our findings.”

Disclosure: Some of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.

This article originally appeared on Pulmonology Advisor