Antibody response following the third and fourth SARS-CoV-2 vaccine dose in individuals with common variable immunodeficiency.

Background: The antibody response after vaccination is impaired in common variable immunodeficiency (CVID).

Objective: We aimed to study the spike receptor-binding domain IgG antibody (anti-S-RBD) levels during a four-dose SARS-CoV-2 vaccination strategy and after monoclonal antibody (mAB) treatment in CVID. Moreover, we assessed the anti-S-RBD levels in immunoglobulin replacement therapy (IgRT) products.