In another approach, SARS-CoV-2 subunit trimer vaccines with the native-like trimeric structure and antigenic epitopes of S protein were designed and were submitted to expression in mammalian cells, which detected high-titer cross-reactive antibodies from previously infected COVID-19 patients (http://www.cloverbiopharma.com/index.php?m=content&c=index&a=lists&catid=42). The gene discussed is PROS1; the disease is COVID-19.