Pfizer-BioNTech COVID-19 Vaccine Effectiveness Study - Kaiser Permanente Southern California

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

Get a concise snapshot of the trial, including recruitment status, study phase, enrollment targets, and key timeline milestones.

Recruitment Status

COMPLETED

Total Enrollment

1 participants

Study Classification

OBSERVATIONAL

Study Start Date

2021-05-15

Study Completion Date

2025-04-30

Brief Summary

Review the sponsor-provided synopsis that highlights what the study is about and why it is being conducted.

The primary objective of this study is to determine the vaccine effectiveness of 2 doses of Pfizer-BioNTech BNT162b2 vaccine against COVID-19-associated hospitalization. There will be a large retrospective database study using two parallel study designs: a test-negative case-control design and a retrospective cohort design. VE estimates by various strata and strain type will be conducted.

Related Clinical Trials

Explore similar clinical trials based on study characteristics and research focus.

A Study of the Effectiveness of Moderna COVID-19 Vaccine

NCT05933304

SARS-CoV-2 COVID-19

COMPLETED

The Efficacy of the 2023-2024 Updated COVID-19 Vaccines Against COVID-19 Infection

NCT06065176

COVID-19 Vaccine-Preventable Diseases SARS CoV 2 Infection +2 more

COMPLETED PHASE4

Estimated Vaccine Effectiveness and Durability of Pfizer/BioNTech 2024-2025 COVID-19 Vaccine

NCT06703190

COVID-19

TERMINATED

COVID-19: A Study to Evaluate Safety, Reactogenicity and Immunogenicity of the SARS-CoV-2 mRNA Vaccine CVnCoV in Adults With Co-morbidities

NCT04860258

Coronavirus Covid19 SARS-CoV-2 +1 more

TERMINATED PHASE3

Evaluation of Inactivated Vaccine in Healthy Adults Against Coronavirus Disease of 2019 (COVID-19)

NCT05128721

COVID-19 Vaccine Reaction Vaccine Adverse Reaction

UNKNOWN PHASE1

Detailed Description

Dive into the extended narrative that explains the scientific background, objectives, and procedures in greater depth.

The primary objective of the study is to estimate vaccine effectiveness (VE) of 2 doses of Pfizer's BNT162b2 vaccine against acute respiratory illness (ARI) requiring hospitalization due to SARS-CoV-2 infection among KPSC members eligible for vaccination. VE will be evaluated using a test-negative design (TND), including all KPSC patients eligible for vaccination who are admitted to the hospital with (ARI) after 14 December 2020 (date of first vaccinations at KPSC), and who receive a PCR test for SARS-CoV-2. Secondary and exploratory objectives may examine VE for 1 dose vaccination, at least 1 dose, \>2 doses, monovalent, bivalent or mixed dosing schedules as well as against ED admission, specific variants, mixed dosing schedules, durability, age cut-offs to align with regulatory authorizations/approvals and other populations of interest. Additionally, we will estimate VE using a full cohort design, including all KPSC members eligible for vaccination.

To assess VE, we propose a large retrospective database study using two parallel study de-signs: a test-negative case-control design and a retrospective cohort design. The TND will assess VE against COVID-19 hospitalization (primary endpoint) and ED admission. The retrospective cohort analysis may assess VE against COVID-19 hospitalization (primary), ICU admission, death, ED admission, and outpatient disease (with no subsequent hospitalization within 14 days). The BNT162b2 BA.4/BA.5 bivalent vaccine effectiveness will only be assessed via a test negative design due to the limitations regarding testing bias. As the pandemic evolved PCR-confirmed testing and reporting became less routine and differences in health care seeking behaviors were seen based on vaccination status.

VE for the XBB1.5-adapted monovalent vaccine will be defined as receipt of Pfizer -BioNTech XBB1.5-adapted monovalent vaccine with greater than or equal to 14 days between receipt of vaccine and the event date.

We will further conduct additional analyses of VE estimates by various patient characteristics and strain types.

Conditions

See the medical conditions and disease areas that this research is targeting or investigating.

COVID-19

Study Design

Understand how the trial is structured, including allocation methods, masking strategies, primary purpose, and other design elements.

Observational Model Type

CASE_CONTROL

Study Time Perspective

RETROSPECTIVE

Study Groups

Review each arm or cohort in the study, along with the interventions and objectives associated with them.

Fully vaccinated

Prior receipt of 2 doses of BNT162b2 received with ≥7 days between receipt of the 2nd dose and the index date. This group will serve as the 'exposed' group evaluated in the primary objective.

Primary Exposure Status of Pfizer-BioNTech COVID-19 Vaccine

Intervention Type BIOLOGICAL

prior administration of Pfizer-BioNTech COVID-19 vaccine; vaccine is not administered in this study

BNT162b2 BA.4/5 bivalent

Intervention Type BIOLOGICAL

Vaccination with a bivalent booster was defined as receipt of the BNT162b2 BA 4/5 bivalent vaccine ≥8 weeks (≥56 days) since the most recent dose of wild-type COVID-19 mRNA vaccine (BNT162b2 or mRNA-1273) received.

Partially vaccinated

Prior receipt of 1 dose (only) of BNT162b2 received with ≥14 days between receipt of the 1st dose and the index date.

Primary Exposure Status of Pfizer-BioNTech COVID-19 Vaccine

Intervention Type BIOLOGICAL

prior administration of Pfizer-BioNTech COVID-19 vaccine; vaccine is not administered in this study

BNT162b2 BA.4/5 bivalent

Intervention Type BIOLOGICAL

Vaccination with a bivalent booster was defined as receipt of the BNT162b2 BA 4/5 bivalent vaccine ≥8 weeks (≥56 days) since the most recent dose of wild-type COVID-19 mRNA vaccine (BNT162b2 or mRNA-1273) received.

Ever vaccinated

Prior receipt ≥1 dose of BNT162b2 received with ≥14 days between index date and receipt of the 1st dose

Primary Exposure Status of Pfizer-BioNTech COVID-19 Vaccine

Intervention Type BIOLOGICAL

prior administration of Pfizer-BioNTech COVID-19 vaccine; vaccine is not administered in this study

Never vaccinated

never received BNT162b2. This group will serve as the reference exposure group (i.e., 'unexposed' group) in all VE analyses

Primary Exposure Status of Pfizer-BioNTech COVID-19 Vaccine

Intervention Type BIOLOGICAL

prior administration of Pfizer-BioNTech COVID-19 vaccine; vaccine is not administered in this study

BNT162b2 BA.4/5 bivalent

Intervention Type BIOLOGICAL

Vaccination with a bivalent booster was defined as receipt of the BNT162b2 BA 4/5 bivalent vaccine ≥8 weeks (≥56 days) since the most recent dose of wild-type COVID-19 mRNA vaccine (BNT162b2 or mRNA-1273) received.

Bivalent vaccinated

Receipt of the BNT162b2 BA.4/5 bivalent vaccine ≥8 weeks (≥56 days) since the most recent dose of wild-type COVID-19 mRNA vaccine (BNT162b2 or mRNA-1273) received

BNT162b2 BA.4/5 bivalent

Intervention Type BIOLOGICAL

Vaccination with a bivalent booster was defined as receipt of the BNT162b2 BA 4/5 bivalent vaccine ≥8 weeks (≥56 days) since the most recent dose of wild-type COVID-19 mRNA vaccine (BNT162b2 or mRNA-1273) received.

XBB.1.5 vaccinated

Receipt of XBB.1.5-adapted monovalent vaccine with greater than or equal 14 days between receipt of vaccine and the event date.

XBB.1.5-adapted vaccinated

Intervention Type BIOLOGICAL

Vaccinated with XBB.1.5-adapted vaccine

Unexposed to XBB.1.5

Unvaccinated with XBB.1.5-adapted monovalent vaccine or any other manufacturer's XBB-adapted formulation.

XBB.1.5-adapted vaccinated

Intervention Type BIOLOGICAL

Vaccinated with XBB.1.5-adapted vaccine

Interventions

Learn about the drugs, procedures, or behavioral strategies being tested and how they are applied within this trial.

Primary Exposure Status of Pfizer-BioNTech COVID-19 Vaccine

prior administration of Pfizer-BioNTech COVID-19 vaccine; vaccine is not administered in this study

Intervention Type BIOLOGICAL

BNT162b2 BA.4/5 bivalent

Vaccination with a bivalent booster was defined as receipt of the BNT162b2 BA 4/5 bivalent vaccine ≥8 weeks (≥56 days) since the most recent dose of wild-type COVID-19 mRNA vaccine (BNT162b2 or mRNA-1273) received.

Intervention Type BIOLOGICAL

XBB.1.5-adapted vaccinated

Vaccinated with XBB.1.5-adapted vaccine

Intervention Type BIOLOGICAL

Other Intervention Names

Discover alternative or legacy names that may be used to describe the listed interventions across different sources.

COVID VACCINE

Eligibility Criteria

Check the participation requirements, including inclusion and exclusion rules, age limits, and whether healthy volunteers are accepted.

Inclusion Criteria

* KPSC patients eligible to receive BNT162b2 who are admitted to the hospital (primary objective and some secondary objectives) with acute respiratory infection (ARI; International Classification of Diseases (ICD) codes) after 14 December 2020 (date of first vaccinations at KPSC), and who receive a PCR test for SARS-CoV-2.
* For secondary objectives estimating VE against ED admission, the TND will include KPSC patients eligible to receive BNT162b2 who present to the ED with ARI after 14 December 2020, and who receive a PCR test for SARS-CoV-2.
* We will include membership requirement of 1 year prior to index date, which is defined as the date of hospitalization or ED admission (allowing 31-day administrative gap), to facilitate accurate capture of comorbid conditions.

* All KPSC members as of 14 December 2020 (date of first Pfizer vaccination at KPSC) eligible to receive BNT162b2.
* For the cohort study, patients must have at least 1 year of membership (allowing 31-day administrative gap) prior to 14 December 2020 (index date, date vaccinations first began at KPSC) to facilitate accurate capture of comorbid conditions.

* KPSC membership for a minimum of 1 year prior to index date, allowing a 30-day gap in membership to allow for delays in renewal. Participants \<1 year did not have a membership requirement.≥6 months of age as of index date
* Admitted to the hospital or had an encounter in the ED, UC, or OP setting with a diagnosis of acute respiratory infection (ARI; defined based on International Classification of Diseases (ICD) codes listed in Appendix Table 1) after 25 September 2023
* Received a SARS-CoV-2 PCR or rapid antigen test

Exclusion Criteria

XBB.1.5-adapted monovalent vaccine eligibility analyses:

* Individuals who received a non-Pfizer-BioNTech XBB.1.5-adapted monovalent vaccine
* Individuals with an index event \<14 days after vaccination with Pfizer-BioNTech XBB.1.5-adapted monovalent vaccine
* Individuals receiving a mRNA bivalent BA4.5 booster ≤ 8 weeks (≤ 56 days) since receiving last wild type dose
* Individuals with \<28 days between a second and subsequent wild type dose
* Individuals receiving a XBB.1.5-adapted monovalent vaccine ≤ 8 weeks (≤ 56 days) since receiving a mRNA bivalent BA4.5 booster
* Individuals receiving oral COVID-19 antiviral OP treatments within 30 days of index event (will be excluded for primary analysis, but included in sensitivity analyses)

Minimum Eligible Age

0 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No