Immunogenicity of the 3rd COVID-19 vaccine dose in Thai healthcare workers at Bamrasnaradura Infectious Diseases Institute

Status

Active, not recruiting

Phases

Unknown

Study type

Observational

Source

TCTR

Registry ID

TCTR20211005001

Enrollment

170

Registered

2021-10-05

Start date

2021-10-08

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

Healthcare workers who received two doses of Sinovac COVID-19 Vaccine SARS-CoV-2 Antibody Healthcare Workers AstraZeneca Pfizer

Interventions

Healthcare workers who received two doses of Sinovac and are receiving the ChAdOx1/AZD1222 vaccine as the 3rd dose. ,None

Prevention,Prevention

ChAdOx1/AZD1222,None

Eligibility

Sex/Gender

All

Age

18 Years to No maximum

Inclusion criteria

Inclusion criteria: 1. Age 18 years or more 2. Healthcare workers at Bamrasnaradura Infectious Diseases Institute 3. Received 2nd dose of Sinovac at least 21 days before 4. Eligible for ChAdOx1/AZD1222 COVID-19 vaccine 5. Informed consent for participation

Exclusion criteria

Exclusion criteria: Allergy to a component of ChAdOx1/AZD1222 COVID-19 Vaccine

Design outcomes

Primary

Measure	Time frame
SARS-CoV-2 antibodies Before vaccination, 4 weeks post vaccination, 12 weeks post vaccination IgG (ELISA), Neutralizaing antibody (NeutraLISA)	—

Secondary

Measure	Time frame
Cellular immunity Before vaccination, 4 weeks post vaccination, 12 weeks post vaccination T cell (Fluorospot), Memory B cell (Fluorospot),COVID-19 infection rate Before vaccination, 1 day post vaccination, 7 days post vaccination, 4 weeks post vaccination, 12 weeks post vaccination Symptom Assessment and confirmed with Real-time RT-PCR if suspected,Adverse events Before vaccination, 1 day post vaccination, 7 days post vaccination, 4 weeks post vaccination, 12 weeks post vaccination Patient report outcomes	—

Measure

Time frame

Cellular immunity Before vaccination, 4 weeks post vaccination, 12 weeks post vaccination T cell (Fluorospot), Memory B cell (Fluorospot),COVID-19 infection rate Before vaccination, 1 day post vaccination, 7 days post vaccination, 4 weeks post vaccination, 12 weeks post vaccination Symptom Assessment and confirmed with Real-time RT-PCR if suspected,Adverse events Before vaccination, 1 day post vaccination, 7 days post vaccination, 4 weeks post vaccination, 12 weeks post vaccination Patient report outcomes

—

Countries

Thailand

Contacts

Public ContactWisit Prasitsirikul

Bamrasnaradura Infectious DIseases Institute

drwisit_p@yahoo.com029511170

Outcome results

None listed

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