Heterologous vaccination strategy for containing COVID-19 pandemic

Lin, A.; Liu, J.; Ma, X.; Zhao, F.; Yu, B.; He, J.; Shen, M.; Huang, L.; Tang, H.; Jiang, E.; Wang, Y.; Cui, P.; Zhang, Y.; Yao, W.; Zhang, A.; Li, Y.; Huang, W.; Li, Q.; Liu, Z.; Li, H.

An unequitable vaccine allocation and continuously emerging SARS-CoV-2 variants pose challenges to contain the pandemic, which underscores the need for licensing more vaccine candidates, increasing manufacturing capacity and implementing better immunization strategy. Here, we report data from a proof-of-concept investigation in two healthy individuals who received two doses of inactivated whole-virus COVID-19 vaccines, followed by a single heterologous boost vaccination after 7 months with an mRNA vaccine candidate (LPP-Spike-mRNA) developed by Stemirna Therapeutics. Following the boost, Spike-specific antibody (Ab), memory B cell and T cell responses were significantly increased. These findings indicate that a heterologous immunization strategy combining inactivated and mRNA vaccines can generate robust vaccine responses and therefore provide a rational and effective vaccination regimen.