Intradermal second booster COVID-19 vaccination

Safety and Immunogenicity of a Second Booster Dose of Intradermal and Intramuscular COVID-19 Vaccines in Thai Older People (Extended Study of Safety and Immunogenicity of Intradermal and Intramuscular Booster COVID-19 Vaccination following the 2-dose primary series of ChAdOx1 (AstraZeneca) in Thai older people)

Status

Active, not recruiting

Phases

Phase 4

Study type

Interventional

Source

TCTR

Registry ID

TCTR20230411008

Enrollment

210

Registered

2023-04-11

Start date

2022-05-08

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

The second booster intradermal mRNA-based vaccine following the 2-dose primary series of ChAdOx1 (AstraZeneca) can provide a sufficient level of immunity against SAR-CoV-2. booster vaccine, SAR-CoV2, older adult, intradermal vaccination, elderly, Thailand

Interventions

0.1 ml mRNA vaccine intradermal injection. Antibody levels are followed at 2-4 weeks. Adverse event is followed for 7 days after injection.,0.3-0.5 ml mRNA vaccine intramuscular injection. Antibody le

Experimental Biological/Vaccine,Active Comparator Biological/Vaccine

intradermal,intramuscular

Eligibility

Sex/Gender

All

Age

65 Years to No maximum

Inclusion criteria

Inclusion criteria: 1. Aged 65 years old or more. 2. Having a 2-dose primary series of ChAdOx1 (AstraZeneca) vaccine for 12-24 weeks followed by a booster mRNA-based vaccine. 3. Stable and well-controlled chronic diseases. 4. Ability to understand and communicate in Thai language. 5. Ability to attend the appointment. 6.Ability to give informed consent

Exclusion criteria

Exclusion criteria: 1. Having a history of anaphylaxis to drug or other vaccines. 2. Having a previous history of Covid-19 infection or high-risk of Covid-19 infection. 3. Having any type of vaccination 2 week before the recruitment. 4. Having any type of immunodeficiency. 5. Taking any type of immunosuppressive agent or cytotoxic drug. 6. Acute illness or acute inflammation. 7. Having blood transfusion or other blood products, immunoglobulin, antiviral agent, or antibody within previous 90 days. 8. Having any skin disease not suitable for intradermal injection.

Design outcomes

Primary

Measure	Time frame
Immunological response 2-4 weeks after vaccination SARSCov-2 IgG by Chemiluminescent microparticle immunoassay (CMIA),Neutralizing antibody assay 2-4 weeks after vaccination percent foci reduction, inhibitory concentration at 50%	—

Secondary

Measure	Time frame
vaccine adverse event 7 days after vaccination number of adverse event	—

Countries

Thailand

Contacts

Public ContactPrasert Assantachai

Faculty of Medicine Siriraj hospital, Mahidol University

prasert.uts@mahidol.ac.th66988323939

Outcome results

None listed

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