The coronavirus disease 2019 (COVID-19) pandemic is a potentially fatal disease that represents a great global public health concern. In European countries such as Spain, Italy, Germany, Portugal, England and France, the pandemic has been of utmost importance. To date, no treatment has been robustly validated, and two theoretically opposite therapeutic strategies are proposed, based either on antiretroviral therapy or on immunomodulating agents.

In this complex context, people living with immune-mediated inflammatory diseases (IMID) raise specific concerns due to their potentially increased risk of infections or of severe infections. Among IMID, Sjögren's syndrome, systemic lupus erythematosus, rheumatoid arthritis, spondyloarthritis and giant cell arteritis are some key diseases.

In this cross-sectional, observational, multi-centric study, the investigators aim to assess both clinical and serological prevalence of COVID-19 among samples of IMID patients in Europe. In parallel, the investigators aim to compare the prevalence of COVID-19 seroconversion across these five IMIDs, their penetration across different 6 European countries (France, Italy, Spain, Germany, United Kingdom and Portugal), and to assess the severity of COVID-19 in these patients. Moreover, changes in treatment will be assessed, including immunomodulatory tapering or discontinuation, its causes over the outbreak period, as well as the incidence of IMID flares and their severity over this same period. Finally, patient's perceptions towards the pandemic will be evaluated and compared to medication beliefs.

Data will be collected through questionnaires during medical visit or phone consultation and serological tests will be performed within routine blood collection. As so, all study procedures are comprised within usual care. Through this study the investigators expect to have a better knowledge of the clinical and serological prevalence of COVID-19 in IMID across Europe, along with the psychological, clinical, and therapeutic impact of COVID-19 in this particular patient population.

Inclusion Criteria:

• Age > 18 years;
• Patients fitting classification criteria for each IMID (i.e., Sjögren's syndrome, systemic lupus erythematosus, rheumatoid arthritis, axial spondyloarthritis or giant cell arteritis);
• Willingness to participate;
• There are no specific inclusion criteria based on IMID previous activity, treatment or known COVID-19.

Exclusion Criteria:

• Patients who refuse to participate;
• Patients who don't speak or read the local language,
• Patients unable to perform a routine blood collection during the study period

Patients followed-up for Sjögren's syndrome, systemic lupus erythematosus, rheumatoid arthritis, spondyloarthritis and giant cell arteritis in selected European tertiary-care centres will be contacted. The required number of patients with definite IMIDs who satisfy the inclusion criteria, followed-up in outpatient visits in the participating centres by one of the investigators, will be asked to participate. Consecutive patients fitting inclusion criteria will be selected in each centre in order to reduce bias selection.