Effectiveness of Inactivated COVID-19 Vaccine of the First Booster Dose

• Conditions: COVID-19
• Interventions: Biological: COVID-19 Vaccine (Vero Cell), Inactivated

• Registration Number: NCT05367895
• Lead Sponsor: Sinovac Research and Development Co., Ltd.

Brief Summary

This is a retrospective test-negative case-control study of COVID-19 Vaccine (CoronaVac®) manufactured by Sinovac Research and Development Co., Ltd.The main purpose of this study is to measure vaccine effectiveness of homologous booster-dose vaccination with CoronaVac® against laboratory-confirmed symptomatic disease.

Detailed Description

This is a retrospective test-negative case-control study in São Paulo city, Brazil . The COVID-19 Vaccine (CoronaVac® )produced by Sinovac Research and Development Co., Ltd.The main purpose of this study is to measure vaccine effectiveness of homologous booster-dose vaccination with CoronaVac® against laboratory-confirmed symptomatic disease.A total of 14000 subjects will be enrolled,including 7,000 positive cases and 7,000 test negative COVID-19 cases The Statistical Analysis Plan (SAP) will include univariate (and, when required, multivariable) models of logistic regression.Data will be recovered from three health surveillance information electronic health records (EHRs):

1. VACIVIDA, comprising individual data for people vaccinated against SARS-Cov-2.

2. E-SUS, mandatory report database for mild to moderate COVID-19.

3. SIVEP-GRIPE, mandatory report database for severe cases of COVID-19. All those RWD sources are available at the São Paulo Municipality Centers for Health Surveillance.

Study Timeline

• Status Verified: 2022-04
• Study First Submitted: 2022-04-28
• Study First Submitted QC: 2022-05-07
• Study First Posted: 2022-05-10
• Study Start: 2022-07-30
• Primary Completion: 2022-08-15
• Last Update Submitted: 2023-01-11
• Last Update Posted: 2023-01-12
• Study Completion: 2023-02-15

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 14000

Inclusion Criteria

• Exposure group 1: Adults (≥ 18 years of age) registered in the E-SUS or SIVEP-gripe RWD source data from August 16th, 2021 through April 21st, 2022 and received a three-dose homologous vaccination with CoronaVac. Specifically, ≥14 days after receipt of the third vaccine dose using a homologous regimen with CoronaVac.
• Exposure group 2: Adults (≥ 18 years of age) registered in the E-SUS or SIVEP-gripe RWD source data from August 16th, 2021 through April 21st, 2022, who received a two-dose vaccination with CoronaVac and did not receive any booster vaccine. Specifically, ≥14 days after receipt of the second vaccine dose and before the third dose of CoronaVac.
• Exposure group 3: Adults (≥ 18 years of age) registered in the E-SUS or SIVEP-gripe RWD source data from August 16th, 2021 through April 21st, 2022, who received only one dose vaccination with CoronaVac and did not receive any other vaccine dose. Specifically, ≥14 days after receipt of the first vaccine dose and before the second dose of CoronaVac.
• Non-Exposure group: Adults (≥ 18 years of age) registered in the E-SUS or SIVEP-gripe RWD source data from August 16th, 2021 through April 21st, 2022, who were not vaccinated. No history of vaccination for any type of COVID-19 vaccine, or <14 days after receipt of the first vaccine of CoronaVac.

Exclusion Criteria

• Anyone who received other vaccines for the first doses.
• Anyone who received CoronaVac for the two initial doses but other vaccines for the booster (heterologous immunization).
• Subjects with incomplete vaccination history.

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Exposure group 2	COVID-19 Vaccine (Vero Cell), Inactivated	Adults (≥ 18 years of age) registered in the E-SUS or SIVEP-gripe RWD source data from August 16th, 2021 through April 21st, 2022, who received a two-dose vaccination with CoronaVac and did not receive any booster vaccine. Specifically, ≥14 days after receipt of the second vaccine dose and before the third dose of CoronaVac.
Exposure group 1	COVID-19 Vaccine (Vero Cell), Inactivated	Adults (≥ 18 years of age) registered in the E-SUS or SIVEP-gripe RWD source data from August 16th, 2021 through April 21st, 2022 and received a three-dose homologous vaccination with CoronaVac. Specifically, ≥14 days after receipt of the third vaccine dose using a homologous regimen with CoronaVac.
Non-Exposure group	COVID-19 Vaccine (Vero Cell), Inactivated	Adults (≥ 18 years of age) registered in the E-SUS or SIVEP-gripe RWD source data from August 16th, 2021 through April 21st, 2022, who were not vaccinated. No history of vaccination for any type of COVID-19 vaccine, or \<14 days after receipt of the first vaccine of CoronaVac.

Primary Outcome Measures

Name	Time	Method
Effectiveness of homologous booster-dose vaccination with CoronaVac®	6 months after the third dose of COVID-19 vaccine	To measure vaccine effectiveness of homologous booster-dose vaccination with CoronaVac® against laboratory-confirmed symptomatic disease

Secondary Outcome Measures

Name	Time	Method
effectiveness of homologous booster-dose vaccination with CoronaVac®	6 months after the third dose of COVID-19 vaccine	To measure vaccine effectiveness of homologous booster-dose vaccination with CoronaVac® against laboratory-confirmed COVID-19 hospital admissions
vaccine effectiveness of homologous booster-dose vaccination with CoronaVac®	6 months after the third dose of COVID-19 vaccine	To measure vaccine effectiveness of homologous booster-dose vaccination with CoronaVac® against laboratory-confirmed COVID-19 intensive care unit admissions.
Vaccine effectiveness of homologous booster-dose vaccination with CoronaVac®	6 months after the third dose of COVID-19 vaccine	To measure vaccine effectiveness of homologous booster-dose vaccination with CoronaVac® against laboratory-confirmed COVID-19 intensive care unit deaths.

Trial Locations

Locations (1)

Instituto Nacional de Infectologia Evandro Chagas (INI-FIOCRUZ); 🇧🇷 Manguinhos, Brazil