GYPC and lassa virus infectious disease: Anti-GPC antibodies that can neutralize Lassa virus have been isolated from Lassa fever survivors.28 Some of these antibodies are being developed as antibody cocktails and there is evidence that they can protect from lethal Lassa virus infection.29–32 In addition, vaccines that elicit antibodies against GPC are also being developed.33–37 However, the high variability of GPC (up to ~8% amino-acid divergence among lineages) raises the specter of antibody and vaccine escape, a problem that has been observed for other viruses—including most recently SARS-CoV-2.38–41