Mixing COVID-19 vaccines: could two different shots be better?
NCT ID NCT05054621
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This study tested whether getting a different COVID-19 vaccine for the second shot (instead of the same one) is safe and boosts immunity. 100 healthy adults who had already received one dose of the AZD1222 vaccine were randomly assigned to get either the same vaccine or a different one (MVC-COV1901) as their booster. Researchers measured immune responses and side effects over 168 days.
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 (AZD1222 and MVC-COV1901)
- What this could lead to
- If mixing vaccines works well, it could offer more flexible and possibly stronger protection against COVID-19.
- What could go wrong
- This is a small, early-phase study with only 100 participants, so results may not apply to everyone. The long-term safety and effectiveness are still unknown.
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
-
ChangGungMH
Taoyuan, Taiwan, 333, Taiwan
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