COVID-19 outcomes in immunocompromised individuals: seroconversion and vaccine effectiveness

Over the past 2 years since the pandemic took hold, those with primary immunodeficiency (PID) have been advised to practice rigorous social distancing, hand hygiene, and if appropriate – COVID-19 vaccination, given the assumption of more severe outcomes. During this period, studies examining the effectiveness of the COVID-19 vaccine and longevity of antibody titers have been instrumental in guiding the need for additional ‘boosters’, allowing for additional protection due to insufficient seroconversion – the development of specific antibodies following vaccination (or exposure to an infectious agent), or waning immunity. Here, we review current data on humoral and cellular responses to the COVID-19 vaccine in individuals with PID, as well as disease course and outcomes of individuals in this cohort who were infected with the SARS-CoV-2 virus.