INTRODUCTION
The coronavirus disease 2019 (COVID-19) outbreak has affected over 500 million individuals and caused over 6 million deaths worldwide since its emergence in 2019 . Severe COVID-19 infections with poorer outcomes have been reported in immunocompromised patients, such as those with inborn errors of immunity (IEI) . Conversely, Marcus et al. reported neither more severe disease nor excess hospital admissions in a cohort of patients with IEI and implied a high awareness level, extra precautions, and even self-isolation as possible explanations . However, preventive measures only provide short-term protection; therefore, vaccination may offer a long-term effective and safe solution.
At present, two mRNA (BNT162b2, also known as Comirnaty, Pfizer/BioNTech; mRNA-173, also known as Spikevax, Moderna), one recombinant-subunit (Novaxovid, Novavax), and two viral-vector (AZD1222, also known as Vaxzevria, AstraZeneca; Ad26.COV2.S, also known as COVID-19 Vaccine Janssen, Janssen/Johnson & Johnson) vaccines have been approved by the European Medicines Agency for COVID-19prevention. The vaccines induce high levels of immunogenicity and efficacy, ranging from 66.9% to 90.4%, and demonstrate a favorable safety profile, with a dominant prevalence of local reactions in the general population . However, severe AEs, such as thromboembolic events or peri- and myocarditis, have been reported . Additionally, evidence regarding their use in specific patient populations is limited, particularly those with heavily impaired antibody production, disturbed cellular immunity, and/or immune system dysregulation.
Common variable immunodeficiency (CVID) is the most prevalent IEI, characterized by impaired vaccination-induced specific antibody production , immune dysregulation, and partially impaired T-cell phenotype and function . Therefore, this study investigated the immunogenicity, safety, and clinical outcomes of the mRNA vaccine BNT162b2 in a cohort of patients with CVID.