Repeat-Dose Toxicity of Candidate Omicron COVID-19 Vaccine in Sprague-Dawley Rats

Due to a large number of mutations in the spike protein and immune escape, Omicron variant (B.1.1.529) has become predominant concern (VOC) strain. To prevent disease, we developed candidate inactivated vaccine (Omicron COVID-19 Vaccine (Vero Cell), Inactivated). evaluate safety vaccine, tested repeat-dose toxicity Sprague-Dawley (SD) rats. The doses were administered randomly three groups: physiological saline solution (control), aluminum adjuvant PBS (adjuvant group), low-dose high-dose omicron vaccines (vaccine group) for 6 weeks. SD rats allowed recover 4 weeks after withdrawal. We evaluated condition rats, including their ophthalmological condition, body weight, food intake, temperature, blood biochemistry, urine, neutralizing antibody, inflammation at injection site, organs weight. In summary, no dose-dependent adverse toxicological changes observed, recovery trend was obvious, which proved preclinical provided evidence clinical trials humans.