These functions were already leveraged for blood donor surveillance during the Zika virus crisis, showing that negative nucleic acid testing and immunoglobulin M (IgM) to immunoglobulin G (IgG) seroconversion in repeat blood donors infected by this flavivirus still coincided with PCR positivity in mature RBCs for up to ~120 days after infection, the average lifespan of a mature RBC (Catala et al., 2022). This evidence concerns the gene CD40LG and infection.