It has been reported that the novel coronavirus (COVID-19) has caused more than 286 million cases and 5.4 million deaths to date. Several strategies have been implemented globally, such as social distancing and the development of the vaccines. Several severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants have appeared, such as Alpha, Beta, Gamma, Delta, and Omicron. With the rapid spread of the novel coronavirus and the rapidly changing mutants, the development of a broad-spectrum multivalent vaccine is considered to be the most effective way to defend against the constantly mutating virus. Here, we evaluated the immunogenicity of the multivalent COVID-19 inactivated vaccine. Mice were immunized by multivalent COVID-19 inactivated vaccine, and the neutralizing antibodies in serum were analyzed. The results show that HB02 + Delta + Omicron trivalent vaccine could provide broad spectrum protection against HB02, Beta, Delta, and Omicron virus. Additionally, the different multivalent COVID-19 inactivated vaccines could enhance cellular immunity. Together, our findings suggest that the multivalent COVID-19 inactivated vaccine can provide broad spectrum protection against HB02 and other virus variants in humoral and cellular immunity, providing new ideas for the development of a broad-spectrum COVID-19 vaccine.

In response to the fast-waning immune response and the great threat of the Omicron variant of concern (VOC) to the public, we report the pilot-scale production of an inactivated Omicron vaccine candidate that induces high levels of neutralizing antibody titers to protect against the Omicron virus. Here, we demonstrate that the inactivated Omicron vaccine is safe and effective in recalling immune responses to the HB02, Omicron, and Delta viruses after one or two doses of BBIBP-CorV. In addition, the efficient productivity and good genetic stability of the manufactured inactivated vaccine is proved. These results support the further evaluation of the Omicron vaccine in a clinical trial.

Widespread vaccination using the oral live attenuated polio vaccine (OPV) and Sabin strain inactivated vaccine (sIPV) have greatly reduced the incidence of polio worldwide. In the period post-polio, the virulence of reversion of the Sabin strain makes the use of OPV gradually becoming one of the major safety hazards. The verification and release of OPV has become the top priority. The monkey neurovirulence test (MNVT) is the gold standard for detecting whether OPV meets the criteria, which are recommended by the WHO and Chinese Pharmacopoeia. Therefore, we statistically analyzed the MNVT results of type I and III OPV at different stages: 1996–2002 and 2016–2022. The results show that the upper and lower limits and C value of the qualification standard of type I reference products in 2016–2022 have decreased compared with the corresponding scores in the 1996–2002 period. The upper and lower limit and C value of the qualified standard of type III reference products were basically the same as the corresponding scores in the 1996–2002. We also found significant differences in the pathogenicity of the type I and III in the cervical spine and brain, with the decreasing trend in the diffusion index of the type I and type III in the cervical spine and brain. Finally, two evaluation criteria were used to judge the OPV test vaccines from 2016 to 2022. The vaccines all met the test requirements under the evaluation criteria of the above two stages. Based on the characteristics of OPV, data monitoring was one of the most intuitive methods to judge changes in virulence.