Safety observation of COVID-19 inactivated vaccine in immature mice

Abstract

Objective To investigate the safety of COVID-19 inactivated vaccine in immature mice. Methods We selected 3-week-old immature BALB/c mice, continuously observed until 7 weeks old after continuous immunization with fully inactivated vaccine (initial strengthening), and sacrificed BALB/c mice at 7 weeks old, and used H&E, Masson, mast cells and Ki-67 staining to analyze the changes of heart, liver, spleen, kidney, lung and brain. In addition, RNA was extracted from important organs such as the heart, liver, spleen, kidney, lung, and brain, and to evaluate whether there was any effect after vaccination through bulk-RNA sequencing. Results After H&E, Masson, mast cells and Ki-67 staining analyses, there are no significant differences between tissues and organs in the vaccine group and the PBS group, and RNA-Seq did not show that the vaccine had any effect on immature mice. Conclusion COVID-19 inactivated vaccine is safe in immature mice.