Comparative Analysis of Anti-COVID-19 (Severe Acute Respiratory Syndrome) Humoral and Memory T Cell Responses in Children With Various Degrees of Immunosuppression:

Adaptive immune responses are essential for clearing viral infections and retention of virus specific memory populations is required for long-term immunity. However, there is still uncertainty about whether adaptive immune responses to SARS-CoV-2 are protective. Such knowledge is of immediate relevance, as it will provide insights into immunity of SARS-CoV-2 infection and thus help define future immunization strategies. Because of the importance of asymptomatic cases in children, a specific study is needed in this population in order to determine their individual and collective protective capacity. This is even truer for immune compromised children that likely have severe forms of the disease with active and prolonged viral replication in whom it is therefore essential to determine the extent of sero conversion but also the quality and duration of the memory responses. For this purpose, we plan to analyze the anti-SARS-CoV-2 humoral and memory T cell responses, in different groups of immuno-compromized children (i.e with different levels/type of immunosuppression; HIV, renal or stem cell transplantation, anti-TNF or methotrexate treatment) and healthy controls seen in 3 University Hospitals, in order to determine the proportion of children with SARS-CoV-2 specific humoral responses, their protective capacity, the magnitude and the quality of the SARS-Cov-2 memory T cells but also their long term persistence at 1 year.