Third Dose Vaccination With AstraZeneca or Pfizer COVID-19 Vaccine Among Adults Received Sinovac COVID-19 Vaccine

Summary

This prospective, multi-center, randomized, observer-blind Phase 2 study. A total of 1320 participants will be divided into 2 groups (660 each) receiving either full dose or half dose of either AZ or PF.

Each group is further stratified into 3 subgroups according to three interval duration in term of days after second dose of SV for 60 to less than 90 days, 90 to less than120 days and 120 to 180 days. Each group will be randomized to receive either AZ or PF in 1:1 ratio.

Subjects who fulfilled eligibility criteria will be randomly assigned to receive either full dose or half dose of AZ or PF in 1:1 ratio as an IM injection in the deltoid muscle at Visit 1 (V1). Subjects will be follow-up for assessing immunity at day 28 (V3), day 60 (V4) and day 90 (V5) and for safety at day 7 (V2), day 28 (V3), day 60 (V4) and day 90 (V5). At least 50% from each subgroup will be randomly selected to provide additional blood at baseline (V1, day 0) and day 28 (V3) to be used for assessment of T-cell-mediated immunity (CMI)

Conditions

• COVID-19 Infection
• COVID-19 VACCINE

Interventions

BIOLOGICAL

AstraZeneca ChAdOx1 AZD1222 vaccine (AZ) full dose

Astrazeneca COVID-19 (ChAdOx1 AZD1222) vaccine: One dose (0.5 ml) contains: COVID-19 Vaccine (ChAdOx1-S\* recombinant) 5 × 10\^10 viral particles (vp) \*Recombinant, replication-deficient chimpanzee adenovirus vector encoding the SARS-CoV-2 Spike glycoprotein. Produced in genetically modified human embryonic kidney (HEK) 293 cells. Administer: Intramuscular (IM) injection in the deltoid muscle

BIOLOGICAL

Pfizer/BioNTech BNT162b2 vaccine (PF) full dose

Pfizer-BioNTech COVID-19 (BNT162b2) vaccine: Diluent: 0.9% sodium chloride (normal saline, preservative-free) Administer: Intramuscular (IM) injection in the deltoid muscle

BIOLOGICAL

AstraZeneca ChAdOx1 AZD1222 vaccine (AZ) half dose

Astrazeneca COVID-19 (ChAdOx1 AZD1222) vaccine: One dose (0.5 ml) contains: COVID-19 Vaccine (ChAdOx1-S\* recombinant) 5 × 10\^10 viral particles (vp) \*Recombinant, replication-deficient chimpanzee adenovirus vector encoding the SARS-CoV-2 Spike glycoprotein. Produced in genetically modified human embryonic kidney (HEK) 293 cells. Administer: Intramuscular (IM) injection in the deltoid muscle

BIOLOGICAL

Pfizer/BioNTech BNT162b2 vaccine (PF) half dose

Pfizer-BioNTech COVID-19 (BNT162b2) vaccine: Diluent: 0.9% sodium chloride (normal saline, preservative-free) Administer: Intramuscular (IM) injection in the deltoid muscle

Sponsors & Collaborators

• Clinixir Co., Ltd.

  collaborator UNKNOWN

• Program Management Unit-C (PMU-C), governed by Ministry of Higher Education, Science, Research and Innovation (MHESI)

  collaborator UNKNOWN

• Mahidol University

  lead OTHER

Principal Investigators

• Punnee Pitisuttithum, MD · Vaccine Trial Centre, Faculty of Tropical Medicine, Mahidol University

• Atibordee Meesing, MD · Faculty of Medicine, Khon Kaen University

• Romanee Chaiwarith, MD,MHS · Faculty of Medicine, Chiang Mai University

• Sarunyou Chusri, MD,PhD · Faculty of Medicine, Prince of Songkla University

• Sira Nanthapisal, MD,PhD · Faculty of Medicine, Thammasat University

• Suppachok Kirdlarp, MD · Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi hospital,Mahidol University

• Suvimol Niyomnaitham, MD,PhD · Mahidol University

• Sarawut Siwamogsatham, MD · Chulalongkorn University

Study Design

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

DOUBLE

Model

PARALLEL

Eligibility

Min Age

20 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2021-09-24

Primary Completion

2022-02-22

Completion

2022-02-22

Countries

• Thailand

Study Locations