Modernatx, Inc.

This trial is not actively recruiting.

This trial has completed recruitment on this platform, and is no longer accepting new referrals.

A clinical trial of investigational COVID-19 booster vaccines for volunteers ages 16 and older

A clinical trial conducted by Moderna is evaluating investigational booster vaccines that may protect against the COVID-19 Omicron variant and other variants.

Trial ID: mRNA-1273-P305 [EudraCT ID: 2022-000063-51]

Trial Details

The mRNA-1273-P305 clinical trial is evaluating the safety and immune response of the investigational booster vaccines that may protect against the COVID-19 Omicron variant and other variants. The investigational Omicron variant vaccines being studied are being compared to a booster dose of Moderna’s COVID-19 vaccine, SPIKEVAX, which is the vaccine that received conditional marketing authorization in the EU. All participants will receive either an investigational Omicron variant vaccine or 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.

Estimated Enrollment

4000 Participants



Eligibility Criteria

Participants must:
  • Be 16 years of age or older
  • Be in good health
  • Have previously received two or three doses of the COVID-19 vaccine
    • Participants who have previously received a third dose must have received an mRNA vaccine (Moderna, Pfizer/BioNTech) as a third dose
    • Participants who have previously received two doses may have received mRNA (Moderna, Pfizer/BioNTech) or non-mRNA (Oxford/AstraZeneca, Janssen) vaccines
Participants must not:
  • Have received a COVID-19 vaccine within the past 90 days
  • Have tested positive for COVID-19 within the past 90 days
  • Have had close contact within the past 14 days to someone diagnosed with COVID-19
  • Have participated in another trial in the past 28 days

What to Expect

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 will either receive one of the investigational Omicron variant vaccines: mRNA-1273.529, mRNA-1273.214, or the already authorized vaccine, SPIKEVAX.
  • Participants will be asked to attend trial site visits including a Screening Visit, a Vaccination Visit, and approximately four to five subsequent trial site visits (Month 1, Month 3, Month 6, and Month 12). Some participants will have a visit at Day 8.
  • Participants will be asked to have up to four scheduled 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.

Insurance is not needed to join this clinical trial, and compensation for participant’s time/travel will be available.

You will need to travel to one of the study clinics taking part in this clinical trial.

Sites are located in the cities/states identified with the red pin:

Frequently Asked Questions (FAQs)