Can a smaller booster dose still protect against COVID-19?
NCT ID NCT05265065
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This study looked at whether a smaller (fractional) dose of the Pfizer-BioNTech COVID-19 booster works as well as the standard dose. It involved 601 healthy adults in Mongolia who had already received two doses of Sinopharm, AstraZeneca, or Sputnik vaccines 6 to 9 months earlier. The goal was to measure immune response and side effects after the booster.
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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
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District Health Centre
Ulaanbaatar, Mongolia
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