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

Study Overview
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Brief Summary
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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
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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): VACIVIDA, comprising individual data for people vaccinated against SARS-Cov-2. E-SUS, mandatory report database for mild to moderate COVID-19. 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.

Official Title
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Effectiveness of CoronaVac® First Booster Dose for Preventing Symptomatic Acute Respiratory Infection Caused by SARS-CoV-2 Virus in Adults in São Paulo City, Brazil: a Retrospective Test-negative Case-control Study

Conditions
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COVID-19

Intervention / Treatment
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* Biological: COVID-19 Vaccine (Vero Cell), Inactivated


Participation Criteria
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Eligibility Criteria
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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.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Exposure group 1<br>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. | Biological: COVID-19 Vaccine (Vero Cell), Inactivated<br>* 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.<br>* Other names: CoronaVac®;|
| Exposure group 2<br>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. | Biological: COVID-19 Vaccine (Vero Cell), Inactivated<br>* 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.<br>* Other names: CoronaVac®;|
| Exposure group 3<br>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<br>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. | Biological: COVID-19 Vaccine (Vero Cell), Inactivated<br>* 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.<br>* Other names: CoronaVac®;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Effectiveness of homologous booster-dose vaccination with CoronaVac® | To measure vaccine effectiveness of homologous booster-dose vaccination with CoronaVac® against laboratory-confirmed symptomatic disease | 6 months after the third dose of COVID-19 vaccine | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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 | 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. | 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. | 6 months after the third dose of COVID-19 vaccine |