A fifth of those who have recovered do not develop immune protection

About twenty percent of people who have recovered from Covid-19 do not develop immune protection against SARS-CoV-2. Researchers at MedUni Vienna came to this conclusion in a study. Protection against docking and penetration into cells of the body is established only if antibodies are formed against the folded receptor-binding domain (RBD) of the spike protein. However, some people cannot do this, perhaps even with current vaccines.

In a follow-up study now published in the specialist journal “Allergy,” allergist and immunologist Valenta and his team analyzed the antibody response of a larger group after mild and severe infection with SARS-CoV-2. The study was carried out with the help of microarray technology developed at MedUni Vienna, where a large number of virus antigens are applied to a microscopic slide by the machine. In addition, overlapping protein fragments (peptides) of these viral antigens were fixed, covering the entire spike protein on which the receptor-binding domain (RBD) is located. With this, SARS-CoV-2 binds to the ACE2 receptor of human cells.

High levels of antibodies against the folded spike protein and especially against the RBD it contains prevent the virus from binding to human body cells, so the conclusion. However, if someone is unable to raise antibodies against the folded RBD, they are poorly protected. The researchers also showed that only the folded RBD, but not the unfolded RBD, generates immune protection upon vaccination. Therefore, since currently used genetic vaccines mimic infection, it is possible that vaccine breakthroughs may be explained by a lack of antibodies against the folded RBD.