Safety and Immunogenicity of a Severe Acute Respiratory Syndrome Coronavirus 2 Spike Subunit Vaccine Stabilized in the Prefusion Conformation by a Second-Generation Molecular Clamp and Evaluated in Adults Aged 18–55 Years: A Randomized, Double-Blind, Active Comparator, Phase I Trial - Summary - MDSpire

Safety and Immunogenicity of a Severe Acute Respiratory Syndrome Coronavirus 2 Spike Subunit Vaccine Stabilized in the Prefusion Conformation by a Second-Generation Molecular Clamp and Evaluated in Adults Aged 18–55 Years: A Randomized, Double-Blind, Active Comparator, Phase I Trial

  • By

  • Keith J Chappell

  • Francesca L Mordant

  • Alberto A Amarilla

  • Naphak Modhiran

  • Benjamin Liang

  • Zheyi Li

  • Julia A Lackenby

  • Noushin Jaberolansar

  • Jake O’Donnell

  • Vivian Kienzle

  • Varsha Kommajosyula

  • Nicolas Tardiota

  • Jillian K Bennet

  • Christina L Henderson

  • Rhiannon L Dalrymple

  • Justin Goh

  • Kym Hoger

  • Marianne Gillard

  • Martina L Jones

  • Karen Hughes

  • Ben Hughes

  • James Barnes

  • Patrick C Reading

  • Charani Ranasinghe

  • Kanta Subbarao

  • Trent P Munro

  • Paul R Young

  • Daniel Watterson

  • November 25, 2025

  • 0 min

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Objective:

To evaluate the safety, tolerability, and immunogenicity of the MC2-stabilized SARS-CoV-2 spike subunit vaccine (UQSC2) compared to the approved NVX-CoV2373 vaccine.

Key Findings:
  • Both UQSC2 and NVX-CoV2373 were well tolerated with comparable safety profiles.
  • UQSC2 elicited a robust increase in neutralizing humoral responses against the Wuhan strain of SARS-CoV-2.
  • The MC2 platform demonstrated potential for rapid vaccine development against emerging variants.
Interpretation:

The findings support the MC2 platform's effectiveness in producing vaccines against SARS-CoV-2 and potentially other respiratory viruses, indicating its utility in emergency responses.

Limitations:
  • The study was limited to a small sample size of 70 participants.
  • The trial duration was only 6 months, which may not capture long-term immune responses.
Conclusion:

UQSC2 is as well tolerated as NVX-CoV2373 and effectively boosts neutralizing immune responses, supporting the MC2 platform's application in vaccine development.

Original Source(s)

Safety and Immunogenicity of a Severe Acute Respiratory Syndrome Coronavirus 2 Spike Subunit Vaccine Stabilized in the Prefusion Conformation by a Second-Generation Molecular Clamp and Evaluated in Adults Aged 18–55 Years: A Randomized, Double-Blind, Active Comparator, Phase I Trial

  • by Keith J Chappell, Francesca L Mordant, Alberto A Amarilla, Naphak Modhiran, Benjamin Liang, Zheyi Li, Julia A Lackenby, Noushin Jaberolansar, Jake O’Donnell, Vivian Kienzle, Varsha Kommajosyula, Nicolas Tardiota, Jillian K Bennet, Christina L Henderson, Rhiannon L Dalrymple, Justin Goh, Kym Hoger, Marianne Gillard, Martina L Jones, Karen Hughes, Ben Hughes, James Barnes, Patrick C Reading, Charani Ranasinghe, Kanta Subbarao, Trent P Munro, Paul R Young, Daniel Watterson

  • November 25, 2025

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