Background: The global impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been profound, with over 760 million confirmed infections and almost 7 million deaths from coronavirus disease 2019 (COVID-19). The pandemic, officially declared in March 2020, has caused significant and irreversible changes in society. COVID-19 continues to pose a serious threat, ranging from asymptomatic cases to severe outcomes such as acute respiratory distress syndrome and organ failure, putting immense pressure on healthcare systems worldwide. The effects of SARS-CoV-2 infection on individuals with primary immunodeficiency (PID) are not yet fully understood. To date, the available research remains scarce, and the results do not yet provide conclusive evidence of a definitive link between PID and severe SARS-CoV-2 infection. In this study we present the clinical course and outcome of COVID-19 in individuals with PID.

Methods: This study is a retrospective analysis involving 65 patients, comprising both pediatric and adult individuals diagnosed with PID, who exhibited symptoms of SARS-CoV-2 infection and tested positive at The Hospital for Sick Children in Toronto, Ontario, Canada. The data was collected from October 2020 to December 2022.

Results: Sixty-five patients (36 children and 29 adults) were enrolled in our study. Our patients were diagnosed with primary immunodeficiency, and categorized as combined immunodeficiency, antibody deficiency, immune dysregulation disorder, phagocyte defect, intrinsic and innate immunity, or autoinflammatory disorder. Each of our patients had their COVID-19 infection confirmed through serology, rapid antigen test, and/or PCR. Among the study participants, 24 individuals had pre-existing lung conditions. At the time of contracting the infection, 42 patients had been vaccinated against SARS-CoV-2. The majority of patients in the study experienced mild to moderate symptoms of COVID-19.

Conclusion: Our patients with PID exhibited mild to moderate symptoms of COVID-19, and all made a full recovery without any complications.

Statement of Novelty: This study sheds light on impact of COVID-19 in individuals with primary immunodeficiency, revealing a noteworthy observation that patients exhibited mild to moderate symptoms, and remarkably, all experienced a complete recovery devoid of complications.