Booster battle: moderna vs. novavax for fourth COVID shot

NCT ID NCT05658523

First seen Jun 27, 2026 · Last updated Jun 27, 2026

Summary

This study tests two different COVID-19 vaccines—Moderna's bivalent mRNA and Novavax's protein-based—as a fourth booster dose in healthy adults who have already had three doses. Researchers will check how well each vaccine boosts the immune system and track any side effects. The goal is to find out which booster is safer and more effective.

What this could mean

Our plain-language read of the trial. This is informational only — not medical advice or a prediction.

Active substance
COVID-19 vaccines (Moderna bivalent mRNA and Novavax protein-based)
What this could lead to
If successful, this could show which booster vaccine works best for a fourth dose, helping guide future vaccination strategies.
What could go wrong
This is a relatively small trial (496 people) and only measures short-term immune response and side effects, not long-term protection against infection or severe disease.

This is an AI summary of the original study and may miss details. Read our disclaimer.

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Conditions

The condition(s) this trial relates to.

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Contacts and locations

Locations

  • Royal Children's Hospital, Murdoch Children's Research Institute

    Melbourne, Victoria, 3052, Australia

More trials for these conditions

Other studies related to the condition(s) this trial covers.