In the ConvP/COVIg PK/PD study, we treated volunteers who were unable to produce antibodies against the coronavirus with convalescent plasma or hyperimmune globulins (COVig). Previously, no studies had been performed to investigate the amount of convalescent plasma or COVig needs to be administered to ensure that the transfused volunteer reaches a sufficient level of antibodies in his/her blood in the weeks or months after the administration of plasma or COVig.

At several timepoints after the administration of the plasma or COVig, blood was taken and the level of antibodies against the coronavirus was measured. Based on these measurements, we built a model that can predict the concentration of antibodies in blood after administration of plasma or COVig in function of the antibody level in the transfused product.

The study showed that plasma that had been collected during the first year of the pandemic from donors recently cured from COVID19 did not contain enough antibodies to provide long-term protection for people without antibodies. The model can however serve as a tool for the design of future studies into the preventive or therapeutic use of these agents.