NCT05265065

Evaluation of Full Versus Fractional Dose of COVID-19 Vaccine Given as a Booster for the Prevention of COVID-19 in Adults in Mongolia.

A Randomised Controlled Trial to Assess the Immunogenicity, Safety and Reactogenicity of Standard Dose Versus Fractional Doses of COVID-19 Vaccine (Pfizer-BioNTech) Given as a Booster Dose After Priming With Sinopharm, AstraZeneca or Sputnik in Healthy Adults in Mongolia

• Status: Completed
• Phase: Phase 3
• Study type: Interventional
• Enrollment: 601 (actual)
• Sponsor: Murdoch Childrens Research Institute · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Accepted

Summary

This clinical trial is a single-blind, randomised study to determine the reactogenicity and immunogenicity of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) vaccine (Pfizer-BioNTech) as booster dose in adults, who have previously received either Sinopharm (BBIBP-CorV®), AstraZeneca (ChAdOx1-S, or Vaxzevria®) or Sputnik V (Gam-COVID-Vac®) as their primary doses 6 to 9 months earlier. Both standard and fractional doses will be tested. Participants are healthy adults aged 18 years or older, with no upper age limit. Procedures will be implemented to ensure participants of all ages (aged 18 and above) are included and that there is an even age distribution (\<50 and ≥50 years) in each group. There will be a total of 6 groups (Sinopharm-standard dose Pfizer, Sinopharm-fractional dose Pfizer, AstraZeneca-standard dose Pfizer, AstraZeneca-fractional dose Pfizer, Sputnik - standard dose Pfizer, Sputnik - fractional dose Pfizer), with 200 participants per group for Sinopharm and 100 for AstraZeneca and Sputnik.

Detailed description

As per brief summary

Conditions

• COVID-19

Interventions

Type	Name	Description
BIOLOGICAL	Tozinameran - Standard Dose	Tozinameran is a single-stranded, 5'-capped messenger RNA (mRNA) produced using a cellfree in vitro transcription from the corresponding DNA templates, encoding the viral spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Dose - 30 µg in 0.3 ml. Liquid for injection. Single dose.
BIOLOGICAL	Tozinameran - Fractional Dose	Tozinameran is a single-stranded, 5'-capped messenger RNA (mRNA) produced using a cellfree in vitro transcription from the corresponding DNA templates, encoding the viral spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Dose - 15 µg in 0.15 ml. Liquid for injection. Single dose.

Timeline

• Start date: 2022-05-27
• Primary completion: 2022-09-30
• Completion: 2024-11-06
• First posted: 2022-03-03
• Last updated: 2026-03-24
• Results posted: 2024-09-19

Locations

1 site across 1 country: Mongolia

Regulatory

• FDA-regulated drug study