Novavax (Gaithersburg, MD, USA) with support from the Coalition for Epidemic Preparedness Innovations (CEPI, Oslo, Norway), is clinically testing their COVID-19 subunit vaccine candidate prepared using the proprietary Sf9/baculovirus recombinant technology platform to generate S protein antigens as done previously for an RSV vaccine candidate (186). Here, PROS1 is linked to COVID-19.