Selective IgA Deficiency and COVID-19 Outcomes: A Nationwide Retrospective Cohort Study

Area of Science:

• Immunology
• Infectious Diseases
• Public Health

Background:

• Selective IgA deficiency (sIgAD) is the most common primary immunodeficiency, linked to recurrent respiratory infections.
• The role of IgA in mucosal immunity is established, but data on COVID-19 outcomes in sIgAD individuals are limited.

Purpose of the Study:

• To investigate the association between sIgAD and SARS-CoV-2 infection risk, recurrent infections, and COVID-19 hospitalization.
• To assess COVID-19 vaccination uptake in individuals with sIgAD.

Main Methods:

• Retrospective population-based cohort study using Israeli electronic health records (2020-2022).
• Included adults (≥18 years) with IgA measurements; sIgAD defined as IgA < 7 mg/dL with normal IgG/IgM.
• Matched 1:4 sIgAD cohort with controls (normal IgA) by age and sex; analyzed infection, hospitalization, and vaccination data.

Main Results:

• The cohort comprised 61,150 individuals (12,230 sIgAD, 48,920 controls).
• No significant difference in primary SARS-CoV-2 infection risk (aOR 1.03).
• Increased odds of recurrent infection (aOR 1.15) and COVID-19 hospitalization (aOR 1.40) in sIgAD group; slightly higher booster vaccination uptake.

Conclusions:

• sIgAD is not linked to increased susceptibility to primary SARS-CoV-2 infection.
• sIgAD is independently associated with recurrent infections and a higher risk of hospitalization after COVID-19.
• Findings emphasize mucosal immunity's role in viral control and suggest closer monitoring for sIgAD patients post-COVID-19.