The US starts a final trial of another COVID-19 vaccine Novavax, Inc. (Nasdaq: NVAX), an American biotechnology company developing next-generation vaccines for serious infectious diseases, announced the initiation of PREVENT-19, its pivotal Phase 3 study in the United States and Mexico to evaluate the efficacy, safety, and immunogenicity of NVX-CoV2373, the Company’s COVID-19 vaccine candidate.