Development of an ideal inactivated vaccine for COVID-19 (mouse lung RNA-seq data)

Since the emergence of coronavirus disease 2019 (COVID-19), there has been a continuous threat to human health. Whole particle virus vaccine (WPV) for COVID-19 has been developed because of its potency, safety, and handling easiness, however, it has been recognized that it is difficult to maintain the particle structure. Here, we established the preparation method for intact COVID-19 WPV that retains the virus particle structure, including spike proteins on the surface, by improving the culture condition and purification process. The effectiveness of the prepared vaccines, intact and non-intact WPV without surface spike proteins, was examined in a mouse model. A single dose of intact WPV effectively induced humoral immunity compared to non-intact WPV, as indicated by higher titers of neutralization antibodies. Both vaccines significantly induced immune responses to suppress virus replication in the lungs. However, more severe vascular damage with massive immune cell infiltration in the vascular smooth muscle cell layer was observed in the lungs of mice vaccinated with non-intact WPV. These results indicate the importance of the structural integrity of WPV in inducing effective and protective immunity. These findings provide significant insight into the development of COVID-19 WPV for practical use.