Synthetic attenuated virus engineering (SAVE) is a new strategy for virus vaccine development. Codon deoptimized means that exchange the codon into the least preferred codon corresponding to the amino acid. It was reported that deoptimal codon may decrease translation efficiency or stop translation. Therefore, if the virus genome is deoptimized, it may also decrease the virus genome replication and growth.

We combined two novel strategies to develop new enterovirus A71 vaccine candidates, including synthetic biotechnology and reverse genetics system, which incorporated codon-deoptimization and high-fidelity determinants. We developed genetic and antigenic-stable vaccine seeds that increased protection spectra of immune response. Currently, no codon-deoptimized/low virulence vaccine of EV-A71 is available in the market.

EV-A71 is a major pathogen causing neurotropic infections in young children, but the efficacy of treatment is limited. Thus, develop an EV-A71 vaccine is urgent. Although some inactivated vaccines have been approved, generation of a low risk attenuated vaccine seed EV-A71 is still necessary. We use the genetic strategy to develop the codon deopmization combined high fidelity reverse genetics viruses for new vaccine design.