SARS-CoV-2 antibody response after a booster dose of the mRNA COVID-19 vaccine (BNT162b2) among Thai children and adolescents aged 5-17 years.

Status

Active, not recruiting

Phases

Phase 4

Study type

Interventional

Source

TCTR

Registry ID

TCTR20230424002

Enrollment

150

Registered

2023-04-24

Start date

2022-05-28

Completion date

Unknown

Last updated

2026-08-03

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Healthy Thai children aged 5-17 years who received two doses of the mRNA vaccine (BNT162b2). children, Booster dose, Third vaccination, SARS-CoV-2, COVID-19, vaccines, mRNA vaccines, Adverse events, Vaccine safety

Interventions

30 microgram/dose (Standard dose), administered intramuscularly 1 dose,15 microgram/dose (Half dose), administered intramuscularly 1 dose,10 microgram/dose (Standard dose), administered intramuscularl

Active Comparator Biological/Vaccine,Experimental Biological/Vaccine,Active Comparator Biological/Vaccine

COVID-19 mRNA vaccine (Comirnaty) purple Cap,COVID-19 mRNA vaccine (Comirnaty) purple Cap,COVID-19 mRNA vaccine (Comirnaty) orange Cap

Eligibility

Sex/Gender

All

Age

5 Years to 17 Years

Inclusion criteria

Inclusion criteria: 1. The subject is aged 5 to less than 18 years. 2. Have received two doses of full dose mRNA COVID-19 vaccine 3. Have received 2nd dose of COVID-19 vaccine for at least 3 months at the time of third vaccination 4. Have no history of detecting SARS-CoV-2 infection 5. Can understand Thai language through speaking, reading, and writing 6. Capable of attending all study visits according to the study schedule

Exclusion criteria

Exclusion criteria: 1. Have any history of severe drug or vaccine allergy (anaphylaxis) 2. Have a history of Myocarditis or pericarditis from the mRNA COVID-19 vaccine 3. Have received any other vaccines within 14 days for live vaccines or 28 days for inactivated vaccines (excepted influenza vaccine) 4. Have body temperature more than equal 38 C or 100.4 F within 24 hours prior received study vaccine 5. Subject who are pregnant 6. Have received blood transfusion, plasma, blood product, blood components, immunoglobulins, antiviral, or antibodies within the last 90 days 7. Have any history of immunodeficiency or received immunosuppressants or received steroids drugs 8. Have any conditions that are considered unsuitable for clinical study by the investigator

Design outcomes

Primary

Measure	Time frame
Anti-spike RBD antibody 2-4 weeks and 16-20 weeks after vaccination Chemiluminescent microparticle immunoassay (CMIA)	—

Secondary

Measure	Time frame
Neutralizing antibody 2-4 weeks after vaccination Neutralizing Antibody Assays,Adverse event 7 days after vaccination Observe local and systemic reactions.	—

Countries

Thailand

Contacts

Public ContactWanatpreeya Phongsamart

Siriraj Hospital Mahidol University

wanatpreeya@gmail.com028660225

Outcome results

None listed

Source: TCTR (via WHO ICTRP) · Data processed: Aug 9, 2026