The effect of COVID-19 pandemic on idiopathic inflammatory myositis patients: a single centre experience

Objective Pandemic caused by coronavirus disease (COVID-19) determines the life of clinicians and patients since 2 years. We have a lot of information about disease course, treatment and protection against virus, but less on the prognosis of infection in patients with idiopathic inflammatory myopathies (IIM). Also few data are available on triggered humoral response and side effects after vaccination. Methods Our goal was to assess by a retrospective cross-sectional study the above data in our cohort (176 IIM patients) by identifying COVID-19 positive patients and follow disease course. Incidence and complications of vaccination were determined by questionnaires. 101 patients volunteered for complex blood test. Results By June 1(st), 2021 significantly higher incidence of COVID 19 infections (34.7%) were identified comparing to the national prevalence (8.2%). A third of these infections occurred asymptomatically or mild. Patients requiring hospitalisation had a significantly longer disease duration and a higher incidence of anti-Jo-1 antibody. All patients infected by COVID-19 became seropositive regardless the immunosuppressive therapy or symptoms severity. 54.3% of the patients received anti-COVID-19 vaccine. 72.3% of patients became seropositive after vaccination. Higher antibody titre against spike protein was detected after Pfizer-BioNTech vaccination compared to others. Patients receiving steroid therapy had decreased post-vaccination antibody response compared to those without steroid treatment. No major post-vaccination infection was observed Conclusion Based on our results, myositis may be associated with an increased risk of COVID-19 infection. Independent risk factor for hospitalisation are longer disease duration and anti-Jo1 positivity. Anti-SARS-CoV2 vaccines seem safe and tolerable and strongly recommended for that population.