Favorable safety and immunogenicity of a combined quadrivalent influenza and recombinant SARS-CoV-2 vaccine in Sprague-Dawley rats for both primary and booster immunization - Summary - MDSpire

Safety and Immunogenic Response of a Novel Combined Quadrivalent Influenza and Recombinant SARS-CoV-2 Vaccine in Sprague-Dawley Rats During Primary and Booster Doses

  • By

  • Jinjin Shao

  • Chengda Zhang

  • Guangbiao She

  • Tian Qin

  • Jinyao Zhang

  • Minxi Fang

  • Dan Zhao

  • Linying Wang

  • Lijuan Xia

  • Qian Yang

  • Lili Zhang

  • Yanling Zhang

  • Siming Zhang

  • Jiahong Wang

  • Zhiqi Xie

  • Yunxiang Chen

  • Ying Chen

  • Enqi Huang

  • Lijiang Zhang

  • July 17, 2026

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Objective:

To evaluate the safety and immunogenicity of a novel combined quadrivalent influenza and recombinant COVID-19 vaccine (Flu-CoV2) in Sprague-Dawley rats.

Approach:
  • Study Design: Three independent studies were conducted: primary immunization (Study 1) and booster immunization following prior influenza (Study 2) or COVID-19 (Study 3) vaccination.
  • Immunogenicity Assessment: Immunogenicity was determined using IgG antibody ELISA, plaque reduction neutralization tests for SARS-CoV-2, and hemagglutination inhibition assays for influenza viruses.
Key Findings:
  • No severe, life-threatening, or fatal adverse reactions occurred during any of the studies.
  • Transient injection-site nodules in adjuvanted groups resolved completely, and all transient post-vaccination shifts in hematologic and biochemical parameters normalized by the end of the recovery period.
  • The Flu-CoV2 vaccine effectively induced strong IgG and neutralizing antibody responses against both influenza and SARS-CoV-2.
  • Administered as a booster, it markedly augmented specific antibody levels in pre-immune models.
Interpretation:

These preclinical data demonstrate a favorable safety profile and potent immunogenicity for the Flu-CoV2 vaccine.

Limitations:
  • The study was conducted in Sprague-Dawley rats, which may limit the generalizability of the findings to humans.
  • Long-term safety and efficacy in humans have yet to be established.
Conclusion:

The findings support further development of the Flu-CoV2 vaccine.

Original Source(s)

Favorable safety and immunogenicity of a combined quadrivalent influenza and recombinant SARS-CoV-2 vaccine in Sprague-Dawley rats for both primary and booster immunization

  • by Jinjin Shao, Chengda Zhang, Guangbiao She, Tian Qin, Jinyao Zhang, Minxi Fang, Dan Zhao, Linying Wang, Lijuan Xia, Qian Yang, Lili Zhang, Yanling Zhang, Siming Zhang, Jiahong Wang, Zhiqi Xie, Yunxiang Chen, Ying Chen, Enqi Huang, Lijiang Zhang

  • July 17, 2026

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