Common Variable Immunodeficiency Disorders, T cell responses to SARS-CoV-2 vaccines and the risk of Chronic COVID-19.

COVID-19 has had a calamitous effect on the global community. In spite of intense study, the immunological response to the infection is only partially understood. In addition to older age and ethnicity, patients with co-morbidities including obesity, diabetes, hypertension, coronary artery disease, malignancy, renal and pulmonary disease, may experience severe outcomes. Some patients with primary and secondary immunodeficiencies also appear to be at increased risk from COVID-19. In addition to their vulnerability to SARS-CoV-2, patients with primary immunodeficiencies (PIDs) often suffer from chronic pulmonary disease and may not respond to vaccines, exacerbating their long-term risks. Patients with Common Variable Immunodeficiency disorders (CVID), the most frequent symptomatic PID in adults and children, have a spectrum of B and T cell defects. It may be possible to stratify their risk of severe COVID-19 based on age, ethnicity, the severity of their T cell defect as well as the presence of other co-morbidities. Patients with CVID and other immunodeficiencies are at risk of chronic COVID-19, a dangerous stalemate between a suboptimal immune response and SARS-CoV-2. Intra-host viral evolution could result in the rapid emergence of vaccine resistant mutants and is a public health emergency. Vaccination and prevention of Chronic COVID-19 in immunodeficient patients is therefore of the highest priority. Having a reliable diagnostic assay for T cell immunity to SARS-CoV-2 is critical for evaluating responses to vaccines in these patients. New treatments such as NZACE2-Pātari for COVID-19, are likely to be of particular benefit to immunodeficient patients, especially those who fail to mount a robust T cell response to vaccines.