An in-depth investigation of the safety and immunogenicity of an inactivated SARS-CoV-2 vaccine [preprint]

Abstract

BACKGROUND: 50 In-depth investigations of the safety and immunogenicity of inactivated SARS-CoV-2 vaccines 51 are needed. 52 METHOD: 53 In a phase I randomized, double-blinded, and placebo-controlled trial involving 192 healthy 54 adults 18-59 years of age, two injections of three different doses (50 EU, 100 EU and 150 EU) 55 of an inactivated SARS-CoV-2 vaccine or the placebo were administered intramuscularly with 56 a 2- or 4-week interval between the injections. The safety and immunogenicity of the vaccine 57 were evaluated within 28 days. 58 FINDING: 59 In this study, 191 subjects assigned to three doses groups or the placebo group completed 60 the 28-day trial. There were 44 adverse reactions within the 28 days, most commonly mild 61 pain and redness at the injection site or slight fatigue, and no abnormal variations were 62 observed in 48 cytokines in the serum samples of immunized subjects. The serum samples 63 diluted from 1:32 to 1:4096 and incubated with the virus did not show antibody-dependent 64 enhancement effects (ADEs) with regard to human natural killer cells, macrophages or 65 dendritic cells. At day 14, the seroconversion rates had reached 92%, 100% and 96% with 66 geometric mean titers (GMTs) of 18.0, 54.5 and 37.1, and at day 28, the seroconversion rates 67 had reached 80%, 96% and 92% with GMTs of 10.6, 15.4 and 19.6in 0, 14 and 0, 28 68 procedures, respectively. Seroconversion was associated with the synchronous upregulation 69 of ELISA antibodies against the S protein, N protein and virion and a cytotoxic T lymphocyte 70 (CTL) response. Transcriptome analysis shaped the genetic diversity of immune response 71 induced by the vaccine. 72 INTERPRETATION: It is made available under a CC-BY-NC-ND 4.0 International license . (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. medRxiv preprint doi: https://doi.org/10.1101/2020.09.27.20189548.this version posted October 6, 2020. The copyright holder for this preprint 4 73 In a population aged 18-59 years, this inactivated SARS-CoV-2 vaccine was safe and 74 immunogenic.