The Burden of COVID-19 in the Immunocompromised Patient: Implications for Vaccination and Needs for the Future

Abstract

Approximately 3% of US adults are immunocompromised and less capable of fighting infections such as SARS-CoV-2 (the causative agent of COVID-19). Individuals may be immunocompromised for reasons related to an underlying medical condition or to immunomodulatory therapies that alter the immune response. In general, vaccination with mRNA-based vaccines is effective at reducing COVID-19-associated hospitalization and death among immunocompromised populations, particularly after 3 or more doses. However, the immunocompromised population is heterogeneous, with COVID-19 vaccine-elicited immune responses and risk for severe COVID-19 existing on a continuum. Therefore, understanding the impact of vaccination and the complexity of immune responses across heterogeneous immunocompromised individuals is essential for guiding effective vaccination regimens including additional (booster) doses. In this article, we provide an overview of the immunocompromised population and the burden of disease attributable to COVID-19, while discussing key opportunities and challenges of vaccinating immunocompromised individuals.

Keywords: COVID-19; SARS-CoV-2; immunocompromise; mRNA vaccine; vaccination.

Figure 1.

Spectrum of COVID-19 risk continuum for the clinically extremely vulnerable immunocompromised population. ^aModerate primary immunodeficiencies include conditions that require ongoing immunoglobulin replacement therapy or primary immunodeficiencies that have confirmed genetic causes (eg, DiGeorge syndrome and Wiskott-Aldrich syndrome). ^bSevere primary immunodeficiencies include combined immunodeficiencies affecting T cells, immune dysregulation (particularly familial hemophagocytic lymphohistiocytosis), and type I interferon defects. Abbreviations: CEV, clinically extremely vulnerable.