This randomized Phase 2 study is to evaluate the Immunogenicity and Safety of a Recombinant New Coronavirus Vaccine (CHO Cell) With Different Doses and Different Immunization Procedures in Healthy People Aged 18 to 59 Years.

A total of 900 subjects are planned to be randomly divided into 2 doses of low-dose experimental vaccine group, 2 doses of high-dose experimental vaccine group, 2 doses of placebo group, 3 doses of low-dose experimental vaccine group, 3 doses of high-dose experimental vaccine group and 3 doses of placebo group, the sample size of each group was 150 cases.

Subjects in the 2 dose group were injected with 2 doses of test vaccine or placebo in the upper arm deltoid muscle according to the 0,1 month immunization program, and subjects in the 3 dose group were injected with 3 doses of test vaccine or placebo in the upper arm deltoid muscle according to the 0, 1, 2 month immunization program.

Results

The Lancet published the results of this study on March 24, 2021.

In the phase 2 trial, the overall frequency of adverse events was low within 30 days after vaccination. Among participants receiving two doses, 37 (25%) of 150 in the placebo group, 43 (29%) of 150 in the 25 μg group, and 50 (33%) of 150 in the 50 μg group reported at least one adverse event. Among participants receiving three doses, 47 (31%) of 150 in the placebo group, 72 (48%) of 150 in the 25 μg group, and 65 (43%) of 150 in the 50 μg group reported at least one adverse event. Within 7 days after each vaccination, most of the local and systemic reactogenicity was mild or moderate (grade 1 or 2 adverse events). The most common solicited local adverse events in participants on the two-dose and three-dose schedules were injection-site pain, swelling, induration, redness, and itch. The most common solicited systemic adverse events in participants on the two-dose and three-dose schedules were fever, cough, headaches, and fatigue. 18 participants reported grade 3 or worse adverse events, and 11 (61%) of these were vaccine-related: redness (six participants: four in the three-dose 50 μg group, one in the three-dose 25 μg group, and one in the two-dose 50 μg group), swelling (three participants in the three-dose 50 μg group), injection-site pain (one participant in the three-dose 25 μg group), induration (one participant in the three-dose 50 μg group), rash (one participant in the three-dose 50 μg group), fever (one participant in the two-dose 25 μg group), headaches (one participant in the two-dose 25 μg group), and cough (one participant in the three-dose placebo group).

Seven participants reported serious adverse events (one [1%] in the two-dose 25 μg vaccine group, one [1%] in the two-dose 50 μg vaccine group, two [1%] in the three-dose placebo group, one [1%] in the two-dose 25 μg vaccine group, and two [1%] in the two-dose 50 μg vaccine group), but none was considered to be related to the study vaccine as assessed by the investigators. No adverse events of special interest were reported.