Liesa van der Aa1, Marijn van der Sluis1, Sandra den Otter1, Frank van Boven1, MW van der Ent1
Background: It is a matter of debate whether patients with Immune-Mediated Diseases (IMD) are at increased risk infection with SARS-Cov-2 and a severe course of disease. The aim of this study was to evaluate the cumulative incidence and severity of COVID-19 among patients with immune-mediated diseases and primary immunodeficiency, taking into account the adherence to social distancing measures.
Methods: A longitudinal cohort study of outpatients of the clinical immunology department of a tertiary medical Centre was conducted, with their household members as control population. Questionnaires regarding COVID-19, severity of disease and adherence to social distancing measures were systematically conducted by telephone. The cumulative incidence was calculated from the beginning of the pandemic until January 29, 2021.
Results: 552 patients (median age 52.4 years (range 18.2-89.0), 61.6% female) with auto-immune/auto-inflammatory diseases or an immunodeficiency and 486 household members (median age 49.8 (range 18.0-88.4) years, 41.8% female) were included. The cumulative incidence of COVID-19 was 8.2% in patients and 9.7% in household members. The hospitalization rate in patients was higher compared to household members (p=0.03). The cumulative incidence of COVID-19 was higher among patients than the general Dutch population (8.2% vs. 5.6%, p<0.001). Adherence to social distancing measures was not associated with lower rates of COVID-19.
Conclusion: The cumulative incidence of COVID-19 was higher among patients with IMD compared to the general population, but similar to their household members, although patients had a more severe course of disease. Adherence to social distancing measures did not appear to influence the cumulative incidence of COVID-19.