(A-351) Autoimmune Disease Risks Across COVID-19 Vaccine Platforms: A Population-Based Cohort Study in Taiwan

Background: COVID-19 vaccines help control the pandemic but have raised safety concerns regarding autoimmune diseases (AID). While most studies focus on mRNA vaccines, the risks of other vaccine platforms like viral vector and protein subunit vaccines are less understood.

Objectives: To compare the risks of AID among recipients of mRNA (Moderna and BNT), viral vector (AZ), and protein subunit (Medigen and Novavax) COVID-19 vaccines in Taiwan.

Methods: We emulated a target trial using Taiwan’s National Health Insurance Research Database and COVID-19 vaccination database. Adults (≥20 years) receiving at least one COVID-19 vaccine between March 22, 2021, and September 23, 2022, were included. Individuals with AID in the past three years were excluded. Participants were grouped by the brand of their first vaccine dose: AZ, Moderna, BNT, Medigen or Novavax. Follow-up began at first dose until AID outcome, death, or study end. The primary outcome was AID classified into ten body systems. Propensity score (PS) weighting adjusted for age, sex, income, comorbidities, and comedications. Cox proportional hazards regression assessed risk differences.

Results: A total of 7,385,094, 4,086,708, 4,775,983, 945,599, and 14,507 individuals received AZ, Moderna, BNT, Medigen, and Novavax vaccines as their first dose, respectively. Mean age ranged from 40.3 to 57 years, with 47.7% to 53.2% male. The Moderna and Novavax groups were older and had more comorbidities. After PS weighting, covariates were balanced. AID incidence ranged from 0.48 to 7.41 per 1,000 person-years. Mucocutaneous disorders were the most common, while gastrointestinal diseases were the least reported. Compared to Medigen, Moderna recipients had higher risks of cardiovascular (HR 1.12), hematopoietic (HR 1.08), kidney and lung (HR 1.15), mucocutaneous (HR 1.14), and musculoskeletal disorders (HR 1.08). However, compared to AZ, they had lower risks of endocrine (HR 0.97), gastrointestinal (HR 0.96), liver (HR 0.93), and mucocutaneous disorders (HR 0.98), except for neuronal diseases (HR 1.07). BNT vaccines had a slightly higher risk of mucocutaneous disorders (HR 1.03) than Medigen, but lower risks for most systems compared to AZ. AZ recipients showed increased risks of endocrine (HR 1.05), hematopoietic (HR 1.08), and mucocutaneous disorders (HR 1.13), but a lower risk of neuronal diseases (HR 0.95) compared to Medigen.

Conclusions: Moderna and AZ vaccines were linked to higher risks of certain autoimmune diseases compared to Medigen, while BNT showed a more favorable safety profile. These findings show generally lower risks of protein subunit vaccine for most autoimmune outcomes but differences between Moderna and BNT suggest that factors beyond vaccine platform may influence autoimmune risk.