摘要：SummaryLive-attenuated vaccines are generally highly effective. Here, we aimed to develop one against SARS-CoV-2, based on the identification of three types of temperature-sensitive (TS) strains with mutations in nonstructural proteins (nsp), impaired proliferation at 37°C–39°C, and the capacity to induce protective immunity in Syrian hamsters. To develop a live-attenuated vaccine, we generated a virus that combined all these TS-associated mutations (rTS-all), which showed a robust TS phenotypein vitroand high attenuationin vivo. The vaccine induced an effective cross-reactive immune response and protected hamsters against homologous or heterologous viral challenges. Importantly, rTS-all rarely reverted to the wild-type phenotype. By combining these mutations with an Omicron spike protein to construct a recombinant virus, protection against the Omicron strain was obtained. We show that immediate and effective live-attenuated vaccine candidates against SARS-CoV-2 variants may be developed using rTS-all as a backbone to incorporate the spike protein of the variants.Graphical abstractDisplay OmittedHighlights•Temperature-sensitive CoV-2 with mutations innsp3,nsp14, andnsp16were isolated•Combination of these mutations led to reduced risk of virulent reversion•Engineered viral strain showed strong immunogenicityin vivo•A live-attenuated vaccine platform with exchangeable spike protein was establishedBiological sciences; Genomics; Immune response; Immunology; Virology
