A replication-defective COVID-19 vaccine has been developed based on human parainfluenza virus type 2 (hPIV2) vector BC-PIV, which expressed the full-length prefusion-stabilized S protein of SARS-CoV-2, termed BC-PIV/S-2PM.159,160 Massive S proteins were incorporated on the viral surface. The gene discussed is PROS1; the disease is COVID-19.