Efficacy and Safety of the RED-Dimer-Based Covid-19 Vaccine ZF2001 in Adults

ABSTRACT

BACKGROUND The ZF2001 vaccine, which contains a dimeric form of the receptor-binding domain ofsevere acute respiratory syndrome coronavirus 2 and aluminum hydroxide as an adjuvant, was shown to be safe, with an acceptable side-effect profile, and immuno-genie in adults in phase 1 and 2 clinical trials. METHODS We conducted a randomized, double-blind, placebo-controlled, phase 3 trial to in. vestigate the efficacy and confirm the safety of ZF2001. The trial was performed at 31 clinical centers across Uzbekistan, Indonesia, Pakistan, and Ecuador;an addi-tional center in China was included in the safety analysis only. Adult participants (218 years of age) were randomly assigned in a 11 ratio to receive a total of three 25-/Lg doses (30 days aparO of ZF2001 or placebo. The primary end point was the occurrence of symptomatic coronavirus disease 2019 (Covid-19), as confirmed on polymerase-chain-reaction assay, at least 7 days after receipt of the third dose. A key secondary efficacy end point was the occurrence of severe-to-critical Covid-19 (including Covid-19-related death) at least 7 days after receipt of the third dose. RESULTS Between December 12, 2020, and December 15, 2021, a total of28,873 participants received at least one dose of ZF2OO1 or placebo and were ineluded in the safety analysis;25,193 participants who had completed the three-dose regimen, for whom there were approximately 6 months of follow-up data, were included in the updated primary efficacy analysis that was conducted at the second data cutoff date of December 15, 2021. In the updated analysis, primary end-point cases were reported in 158 of 12,625 participants in the ZF2001 group and in 580 of 12,568 participants in the placebo group, for a vaccine efficacy of 75.7°/0 (95°6 confidence interval [CI], 71.0 to 79.8). Severe-to-critical Covid-19 occurred in 6 participants in the ZF2001 group and in 43 in the placebo group, for a vaccine efficacy of 87.6% (95% CI, 70.6 to 95.7);Covid-19-related death occurred in 2 and 12 participants, respectively, for a vaccine efficacy of 86.5% (95% CI, 38.9 to 98.5). The incidence of adverse events and serious adverse events was balanced in the two groups, and there were no vaccine-related deaths. Most adverse reactions (98.590) were of grade 1 or 2. CONCLUSIONS In a large cohort of adults, the ZF2001 vaccine was shown to be safe and effective against symptomatic and severe-to-critical Covid-19 for at least 6 months after full vaccination. (Funded by the National Science and Technology Major Project and others;ClinicalTrials.gov number, NCT04646590.). [ FROM AUTHOR] Copyright of New England Journal of Medicine is the property of New England Journal of Medicine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)