NEW—Chinese phase 2 trial finds #COVID19 vaccine is safe and induces an immune response hubs.ly/H0sK2nR0 
Phase 2 randomised controlled trial of a recombinant adenovirus type-5-vectored #COVID19 vaccine (Ad5-vectored COVID-19 vaccine) was conducted in China in April 2020 and involved more than 500 people
The primary objective of the study was to evaluate the immune response and safety of the vaccine, and to determine the most suitable dose for a phase 3 trial hubs.ly/H0sK2nR0
The trial found that 95% (241/253) of participants in the high dose group & 91% (118/129) of the recipients in the low dose group showed either T cell or antibody immune responses at day 28 post-vaccination
Vaccine induced a neutralising antibody response in 59% (148/253) & 47% (61/129) participants, & binding antibody response in 96% (244/253) & 97% (125/129) participants, in high & low dose groups, respectively, by day 28. Participants in placebo group showed no antibody increase
Both vaccine doses induced significant neutralising antibody responses to live SARS-CoV-2, with GMT of 19.5 & 18.3 in participants receiving high & low dose, respectively. Binding antibody response peaked at 656.5 & 571 ELISA units for high & low vaccine dose, respectively
T cell responses were noted in 90% (227/253) & 88% (113/129) of participants receiving high & low vaccine dose, resp. Median of 11 spot-forming cells & 10 spot-forming cells per 1×10⁵ peripheral blood mononuclear cells in high & low dose group participants were noted at day 28
Solicited adverse reactions were reported by 183 (72%) of 253 participants in high dose group & 96 (74%) of 129 in low dose group. Severe adverse reactions were reported by 24 (9%) participants in high dose group & 1 (1%) in low dose. No serious adverse reactions were noted
Phase 3 trials are needed to confirm whether the vaccine candidate effectively protects against SARS-CoV-2 infection hubs.ly/H0sK2nR0
