Efficacy and antigen dosage
infection, SARS-CoV-2-specific memory T
ASYMPTOMATIC COVID-19, INFECTION, COVID-19 INFECTION
ELISPOT results show that this vaccine can induce SARS-CoV-2-specific memory T cells (Although phase II aims to determine the optimal dose of antigens, in this study, we also evaluated the efficacy of this vaccine in preventing the onset of moderately and severely symptomatic COVID-19 that requires hospital treatment. From a follow-up for 1 year, six subjects experienced moderate–severe symptomatic COVID-19 infection that required hospital treatment in phase II subjects. Thus, it was found that this vaccine protected 95.56% (intention-to-treat analysis, N = 138) of subjects from hospitalization due to COVID-19 for up to 1 year. When compared between dose groups, the proportion of subjects infected with COVID-19, both mild degrees undergoing self-isolation and severe degrees requiring hospital treatment, did not differ significantly. Therefore, there was no difference in efficacy between dose groups in preventing COVID-19 infection and preventing hospitalization. Based on its safety profile and immunogenicity for up to 28 days, the 0.1 mcg antigen dose group was designated as the optimal dose. In the evaluation for up to 1 year, there was no significant difference between the antigen dose groups in preventing the onset of moderately and severely symptomatic COVID-19, thus further supporting the selection of a dose of 0.1 mcg as the most optimal antigen dose formulation.Clinical trials of conventional COVID-19 vaccines mostly use humoral responses to assess vaccine immunogenicity, although correlates of protection from COVID-19 vaccines have not yet been established (Compared to the results of clinical trials of conventional vaccines, the proportion of COVID-19 AE incidence up to 1 year in this vaccine tends to be higher. However, this is likely because this study is a phase II clinical trial with a small number of subjects (AE COVID-19 up to 1 year COVID-19 vaccine clinical trial.The meaning of bold values are the result from our study. 