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

Sinovac Research and Development Co., Ltd.14,000 enrolled

Overview

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.

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 Type

OBSERVATIONAL

Enrollment

14,000

Conditions

COVID-19

Interventions

COVID-19 Vaccine (Vero Cell), InactivatedBIOLOGICAL

Form: CoronaVac® is a milky-white suspension. Stratified precipitate may form that can be dispersed by shaking. Presentation: Each vial contains 0.5 mL (a single dose) and contains 600SU of inactivated SARS-CoV-2 virus antigen. Administration and schedule: Two doses with an interval of 21 days should be administered for primary immunization. 0.5 mL per dose. Route: IM in the deltoid region of the upper arm after shaking the vial well before use.

Eligibility

Sex: ALLMin age: 18 YearsHealthy volunteers:

Medical Language ↔ Plain English

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.

Locations (1)

Instituto Nacional de Infectologia Evandro Chagas (INI-FIOCRUZ)

Manguinhos, Brazil

Outcomes

Primary Outcomes

Effectiveness of homologous booster-dose vaccination with CoronaVac®

To measure vaccine effectiveness of homologous booster-dose vaccination with CoronaVac® against laboratory-confirmed symptomatic disease

Time frame: 6 months after the third dose of COVID-19 vaccine

Secondary Outcomes

effectiveness of homologous booster-dose vaccination with CoronaVac®

To measure vaccine effectiveness of homologous booster-dose vaccination with CoronaVac® against laboratory-confirmed COVID-19 hospital admissions

Time frame: 6 months after the third dose of COVID-19 vaccine

vaccine effectiveness of homologous booster-dose vaccination with CoronaVac®

To measure vaccine effectiveness of homologous booster-dose vaccination with CoronaVac® against laboratory-confirmed COVID-19 intensive care unit admissions.

Time frame: 6 months after the third dose of COVID-19 vaccine

Vaccine effectiveness of homologous booster-dose vaccination with CoronaVac®

To measure vaccine effectiveness of homologous booster-dose vaccination with CoronaVac® against laboratory-confirmed COVID-19 intensive care unit deaths.

Time frame: 6 months after the third dose of COVID-19 vaccine

Data from ClinicalTrials.gov

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