A Phase 2/3, Randomized, Observer-blind, Active-controlled, Multicenter Study to Evaluate the Immunogenicity and Safety of Omicron Variant Vaccines in Comparison with mRNA-1273 (Prototype) Booster Vaccine 

A clinical trial conducted by Moderna is evaluating an investigational booster vaccine that may protect against the COVID-19 Omicron variant.

Status: In Follow-Up 

Population: Adult  

Disease group: COVID-19

Funder: ModernaTX, Inc. 

Sponsor: ModernaTX, Inc.  

Principal Investigator: Dr. Catherine Cosgrove

Study Aims 

The purpose of this study is to compare how the body responds (the “immune response”) to the booster dose of mRNA-1273.529 or mRNA-1273.214 (Omicron variant study vaccines) with authorised Moderna mRNA-1273 vaccine (Spikevax).  

With different strains of COVID-19, there is an urgent need to develop vaccination plans that will provide greater protection. A booster vaccine that protects against COVID-19 variants, including the Omicron variant, would be a crucial public health tool to help curb the pandemic. 

 This study will also test the safety of these vaccines by recording the number of side effects. 

What does participating in the study involve?  

Participation in this clinical trial lasts up to 13 months and includes phone calls and visits to the trial site. 

  • Participants will be given one injection in the upper arm.  
  • Participants in Part 1 of the study will either receive mRNA-1273.529 (Omicron variant vaccine), or the already authorized vaccine, Spikevax. 
  • Participants in Part 2 of the study will either receive the bivalent vaccine, mRNA-1273.214 (Omicron variant plus original vaccine), or the already authorized vaccine, Spikevax. 
  • Participants will be asked to attend trial site visits including a Screening + Vaccination Visit, and approximately five subsequent trial site visits (Day 8, Month 1, Month 3, Month 6, and Month 12).  
  • Participants will be asked to have up to four phone calls with the clinical trial doctor to monitor for any symptoms. During these phone calls, the doctor and medical staff will check how you are feeling and ask for updates on your health. 
  • Participants will be asked to use an eDiary app on your smartphone or a provided smartphone to report any COVID-19 symptoms you experience. 
  • Participants will be closely monitored by the clinical trial team if any symptoms of COVID-19 are reported at any time throughout their participation. 

For more information about the study please visit:

The trial website: https://connect.trialscope.com/studies/7dff1448-9e85-4beb-81a4-ec4f9170c769  

Contact the trial email: moderna-omicron@sgul.ac.uk  

Find out more about the study on the Participant Information Sheet