Due to the likeness between SARS-CoV-2 and other betacoronaviruses, it is likely that target antigen selection and vaccine platform have been based on SARS-CoV and MERS-CoV. The full-length spike or S1 (which contains receptor binding domains) that is employed in DNA, viral vector, and subunit vaccines show promise because they have induced neutralizing antibodies in clinical and preclinical studies of SARS-CoV and MERS-CoV, with the DNA vaccine making the most advancement in clinical trials.