SLE Flares Post COVID-19 Vaccine

September 29, 2022

A study published in Lupus Science & Medicine analyzed the association between mRNA Covid-19 vaccination and SLE flare-ups using subjective and objective methods of measuring disease activity.

74 patients with SLE who received a COVID-19 primary series (Pfizer or Moderna) were each matched with an unvaccinated SLE patient (74 total). Co-morbidities included Rheumatoid Arthritis, Sjogren’s Syndrome, and Mixed Connective Tissue Disease. “There were no significant differences in patients’ characteristics, including age, sex, disease duration and medications, between the two groups. The baseline serological disease activity and disease activity scores did not differ. In the vaccinated group, 16 out of 74 (21%) patients had high disease activity.”

Using three methods to measure disease activity – including the SLE Disease Activity Index-2000 (SLEDAI-2K) and a variation of the SLE Symptom Checklist Questionnaire – researchers measured flares at the 30, 60, and 90 day mark after a completed primary series. Disease activities were also assessed prior to first vaccination and after the second vaccination; disease activities up to three months prior to the initial index date were used as a baseline for each patient. 

“The quantitative changes in the SLEDAI-2K scores from the prefirst vaccination baseline to 30 days after the second vaccination were not significantly different between the vaccinated and unvaccinated groups.” Results were similar after adjusting for sex, age, SLEDAI-2K at baseline, and the use of immunosuppressive therapies or biologics (amongst others, including Glucocorticoids). The rate of mild or moderate SLE flares 30 days after the completion of a primary series was 20.3% within the vaccinated group, versus 23.3% in the unvaccinated group. Flare rates at 60 and 90 days were similar between both groups. 

“Serological disease activity indices showed no clinically significant differences at 30 days after vaccination.” However, platelet count was lower and C3 (protein activity) was higher in the vaccinated group compared to the unvaccinated group. Simply put, high C3 complement levels indicate an inflammatory response.

While symptoms like arthritis and joint pain have been previously observed as the most common short-term symptoms following vaccination, musculoskeletal symptoms showed no significant difference between both groups in the study.