Shielding the immunocompromised: COVID-19 prevention strategies for patients with primary and secondary immunodeficiencies.

The COVID-19 pandemic has significantly impacted immunocompromised patients, particularly those with inborn errors of immunity (IEI), transplant recipients, hematologic malignancies, and those undergoing treatment with immunosuppressive biologics and medications. These patients face an elevated risk of experiencing severe or even fatal consequences following SARS-CoV-2 infections. Vaccination is the primary defense against COVID-19; however, immune responses following immunization are often suboptimal in these patients, with variable specific humoral response rates. Despite the expedited regulatory approval and the widespread implementation of COVID-19 vaccines, the efficacy and safety for immunocompromised populations require thorough investigation. In future pandemics, including vulnerable populations (VPs) in vaccine and monoclonal antibody (mAb) trials is crucial to develop safe, effective immunization strategies, address gaps in vaccine efficacy and safety data, and create tailored guidelines for at-risk groups. This review provides a comprehensive examination of the efficacy of COVID-19 vaccines and mAbs in patients with primary and secondary immunodeficiency, with a specific focus on individuals with IEI, considering previous regulatory aspects and the necessity of including VPs in vaccine trials to enhance the quality of patient care and promote equitable health outcomes in future pandemics.