The antibody and T cell responses of both the upper and lower-airway challenges were recorded before and after administration of the vaccine. The vaccine candidates were able to produce higher antibody levels than convalescent-phase human serum. Th1 responses were induced in all vaccine candidates and negligible Th2 responses were observed. Viral replication was eliminated in the nose and limited in the lungs of the vaccine candidates. This vaccine provided rapid protection and neutralizing activity in the upper and lower airways without damaging the tissues. Because nonhuman primates and humans are similar in nose and lung environments and it is assumed that a vaccine that performs will in primates will produce similar effects in humans. This information was used to determine that mRNA-1273 vaccines were ready for Phase 1 human trials. The active was published in July and updated in August 2020.