Emerg Microbes Infect. 2021 Jul 1:1-48. doi: 10.1080/22221751.2021.1951126. Online ahead of print.
Safe and effective vaccines are still urgently needed to cope with the ongoing COVID-19 pandemic. Recently, we developed a recombinant COVID-19 vaccine (V-01) containing fusion protein (IFN-PADRE-RBD-Fc dimer) as antigen verified to induce protective immunity against SARS-CoV-2 challenge in pre-clinical study, which supported progression to Phase Ⅰ clinical trials in humans. A Randomized, double-blind, placebo-controlled phase I clinical trial was initiated at the Guangdong Provincial Center for Disease Control and Prevention (Gaozhou, China) in February, 2021. Healthy adults aged between 18 and 59 years and over 60 years were sequentially enrolled and randomly allocated into three subgroups (1:1:1) either to receive vaccine (10, 25, and 50μg) or placebo (V-01: Placebo=4:1) intramuscularly with a 21-day interval by a sentinel and dose escalation design. The data showed promising safety profile with approximately 25% vaccine related overall adverse events within 30 days and no grade 3 or worse adverse events. Besides, V-01 provoked rapid and strong immune responses, elicited substantially high-titre neutralizing antibodies and anti-RBD IgG peaked at day 35 or 49 after first dose, presented with encouraging immunogenicity at low dose (10μg) subgroup and elderly participants, which showed great promise to be used as all-aged (18 and above) vaccine against COVID-19. Taken together, our preliminary findings indicate that V-01 is safe and well tolerated, capable of inducing rapid and strong immune responses, and warrants further testing in phase Ⅱ/Ⅲ clinical trials.