Preclinical evaluation of a SARS-CoV-2 mRNA vaccine PTX-COVID19-B Journal Articles uri icon

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  • Safe and effective vaccines are needed to end the COVID-19 pandemic. Here, we report the preclinical development of a lipid nanoparticle–formulated SARS-CoV-2 mRNA vaccine, PTX-COVID19-B. PTX-COVID19-B was chosen among three candidates after the initial mouse vaccination results showed that it elicited the strongest neutralizing antibody response against SARS-CoV-2. Further tests in mice and hamsters indicated that PTX-COVID19-B induced robust humoral and cellular immune responses and completely protected the vaccinated animals from SARS-CoV-2 infection in the lung. Studies in hamsters also showed that PTX-COVID19-B protected the upper respiratory tract from SARS-CoV-2 infection. Mouse immune sera elicited by PTX-COVID19-B vaccination were able to neutralize SARS-CoV-2 variants of concern, including the Alpha, Beta, Gamma, and Delta lineages. No adverse effects were induced by PTX-COVID19-B in either mice or hamsters. Based on these results, PTX-COVID19-B was authorized by Health Canada to enter clinical trials in December 2020 with a phase 2 clinical trial ongoing.


  • Liu, Jun
  • Budylowski, Patrick
  • Samson, Reuben
  • Griffin, Bryan D
  • Babuadze, Giorgi
  • Rathod, Bhavisha
  • Colwill, Karen
  • Abioye, Jumai A
  • Schwartz, Jordan A
  • Law, Ryan
  • Yip, Lily
  • Ahn, Sang Kyun
  • Chau, Serena
  • Naghibosadat, Maedeh
  • Arita, Yuko
  • Hu, Queenie
  • Yue, Feng Yun
  • Banerjee, Arinjay
  • Hardy, W Rod
  • Mossman, Karen
  • Mubareka, Samira
  • Kozak, Robert A
  • Pollanen, Michael S
  • Martin Orozco, Natalia
  • Gingras, Anne-Claude
  • Marcusson, Eric G
  • Ostrowski, Mario A

publication date

  • January 21, 2022

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