COVID‑19 & Breakthrough Infection in Patients with Systemic Autoimmune and Inflammatory Diseases

December 15, 2022

Idiopathic inflammatory myopathies (IIM) are a group of systemic autoimmune disorders, with subgroups such as dermatomyositis and polymyositis. COVID-19 infection is of special concern to patients with IIM and other systemic autoimmune and inflammatory diseases (SAIDs), as they often take immunosuppressive and immunomodulatory therapies for co-morbidities related to their disease. While the data is scarce, an additional concern is that immunosuppressive and immunomodulatory therapies may reduce the efficacy of COVID-19 vaccines in these populations. 

To address these concerns, authors of a recent study analyzed 10,900 self-reported patient responses from the COVAD online global survey. The survey included data regarding COVID-19 severity and breakthrough infections (defined as an infection at least two weeks after a first or second dose of the COVID-19 vaccine) in IIM and SAIDs patients, from April to September 2021.

Based on the COVAD data, 1.4% of patients with IIM, 1.9% of patients with SAIDs, and 3.2% of healthy controls experienced breakthrough infections. Among 17 IIM patients who experienced breakthrough infection, 13 were on immunosuppressants, and three needed hospitalization. Data analysis showed that using immunosuppressants was associated with a higher risk of breakthrough infection.

Participants in the study received at least one dose of a COVID-19 vaccine. Due to the small number of breakthrough cases, authors couldn‘t reliably define whether any specific vaccine type lead to increased chances of breakthrough infection.

Among the patients who filled out the survey, 6.2% of unvaccinated IIM patients reported testing positive for COVID-19, less than SAIDs patients (10.5%) or healthy controls (14.6%). The lower number of COVID-19 cases among IIM patients is likely due to the protective measures taken by these patients. That being said, the chance of IIM patients being hospitalized for COVID-19 was higher than healthy controls. For unvaccinated responders, 30% of IIM patients were hospitalized, compared to 8% of healthy controls.