Landmark trial proves mRNA vaccine stops COVID-19

NCT ID NCT04368728

Vaccine Sponsor: BioNTech SE Source: ClinicalTrials.gov ↗

First seen Jun 27, 2026 · Last updated Jun 27, 2026

Summary

This large study tested the safety and effectiveness of the Pfizer-BioNTech mRNA vaccine (BNT162b2) against COVID-19 in nearly 47,000 healthy volunteers aged 12 and older. Participants received two doses of the vaccine or a placebo, and the trial also explored booster doses and protection against new variants. The results showed the vaccine was highly effective at preventing COVID-19, leading to its emergency use authorization.

This is an AI summary of the original study and may miss details. Read our disclaimer.

Study facts

What this study's own registry entry says, in plain language.

Phase

Phase 2/3

Runs two stages together: whether the treatment works, then large-scale confirmation.

Participants

46,969 people

The number who actually took part.

Started

Apr 2020

Finished

Feb 2023

Lead sponsor

A company

The lead sponsor is a pharmaceutical, biotech, or medical-device company.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Ages

12 years and older

Sex

Anyone

Healthy volunteers

Accepted

You do not need to have the condition being studied to take part.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: • Male or female participants between the ages of 18 and 55 years, inclusive, 65 and 85 years, inclusive, or ≥12 years, inclusive, at randomization (dependent upon study phase). For the boostability and protection-against-VOCs subset: Existing participants enrolled to receive a third dose of BNT162b2 at 30 µg or BNT162b2SA; male or female participants between the ages of 18 and 55 years, inclusive, at rerandomization. Newly enrolled participants enrolled to receive 2 doses of BNT162b2SA; male or female participants between the ages of 18 and 55 years, inclusive, at enrollment. Existing participants enrolled to receive a third dose of BNT162b2 at 5 or 10 µg; male or female participants ≥18 years at rerandomization. Note that participants \<18 years of age cannot be enrolled in the EU. * Participants who are willing and able to comply with all scheduled visits, vaccination plan, laboratory tests, lifestyle considerations, and other study procedures. * Healthy participants who are determined by medical history, physical examination, and clinical judgment of the investigator to be eligible for inclusion in the study. * Participants who, in the judgment of the investigator, are at risk for acquiring COVID-19. * Boostability and protection-against-VOCs existing participant subset only: Participants who provided a serum sample at Visit 3, with Visit 3 occurring within the protocol-specified window. * Capable of giving personal signed informed consent Exclusion Criteria: * Other medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study. * Phases 1 and 2 only: Known infection with human immunodeficiency virus (HIV), hepatitis C virus (HCV), or hepatitis B virus (HBV). * History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the study intervention(s). * Receipt of medications intended to prevent COVID 19. * Previous clinical (based on COVID-19 symptoms/signs alone, if a SARS-CoV-2 NAAT result was not available) or microbiological (based on COVID-19 symptoms/signs and a positive SARS-CoV-2 NAAT result) diagnosis of COVID 19 * Phase 1 only: Individuals at high risk for severe COVID-19, including those with any of the following risk factors: * Hypertension * Diabetes mellitus * Chronic pulmonary disease * Asthma * Current vaping or smoking * History of chronic smoking within the prior year * BMI \>30 kg/m2 * Anticipating the need for immunosuppressive treatment within the next 6 months * Phase 1 only: Individuals currently working in occupations with high risk of exposure to SARS-CoV-2 (eg, healthcare worker, emergency response personnel). * Immunocompromised individuals with known or suspected immunodeficiency, as determined by history and/or laboratory/physical examination. * Phase 1 only: Individuals with a history of autoimmune disease or an active autoimmune disease requiring therapeutic intervention. * Bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection. * Women who are pregnant or breastfeeding. * Previous vaccination with any coronavirus vaccine. * Individuals who receive treatment with immunosuppressive therapy, including cytotoxic agents or systemic corticosteroids, eg, for cancer or an autoimmune disease, or planned receipt throughout the study. * Phase 1 only: Regular receipt of inhaled/nebulized corticosteroids. * Receipt of blood/plasma products or immunoglobulin, from 60 days before study intervention administration or planned receipt throughout the study. * Participation in other studies involving study intervention within 28 days prior to study entry through and including 6 months after the last dose of study intervention, with the exception of non-Pfizer interventional studies for prevention of COVID 19, which are prohibited throughout study participation. * Previous participation in other studies involving study intervention containing lipid nanoparticles. * Phase 1 only: Positive serological test for SARS-CoV-2 IgM and/or IgG antibodies at the screening visit. * Phase 1 only: Any screening hematology and/or blood chemistry laboratory value that meets the definition of a ≥ Grade 1 abnormality. * Phase 1 only: Positive test for HIV, hepatitis B surface antigen (HBsAg), hepatitis B core antibodies (HBc Abs), or hepatitis C virus antibodies (HCV Abs) at the screening visit. * Phase 1 only: SARS-CoV-2 NAAT-positive nasal swab within 24 hours before receipt of study intervention. * Investigator site staff or Pfizer employees directly involved in the conduct of the study, site staff otherwise supervised by the investigator, and their respective family members.

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Conditions

The condition(s) this trial relates to.

Coronavinae infectious disease COVID-19 prevention target

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

COVID-19 SARS-CoV-2 infection

Contacts and locations

Locations

Acevedo Clinical Research Associates

Miami, Florida, 33142, United States
Acibadem Atakent Hastanesi

Istanbul, 34303, Turkey (Türkiye)
Alliance for Multispecialty Research

Coral Gables, Florida, 33134, United States
Alliance for Multispecialty Research, LLC

Mobile, Alabama, 36608, United States
Alliance for Multispecialty Research, LLC

Tempe, Arizona, 85281, United States
Alliance for Multispecialty Research, LLC

Newton, Kansas, 67114, United States
Alliance for Multispecialty Research, LLC

Wichita, Kansas, 67207, United States
Alliance for Multispecialty Research, LLC

Knoxville, Tennessee, 37909, United States
Alliance for Multispecialty Research, LLC

Knoxville, Tennessee, 37920, United States
Amici Clinical Research

Raritan, New Jersey, 08869, United States
Anaheim Clinical Trials, LLC

Anaheim, California, 92801, United States
Atlanta Center for Medical Research

Atlanta, Georgia, 30331, United States
Aventiv Research Inc.

Columbus, Ohio, 43213, United States
Bayview Research Group

Valley Village, California, 91607, United States
Benaroya Research Institute at Virginia Mason

Seattle, Washington, 98101, United States
Benchmark Research

Metairie, Louisiana, 70006, United States
Benchmark Research

Austin, Texas, 78705, United States
Benchmark Research

Fort Worth, Texas, 76135, United States
Benchmark Research.

San Angelo, Texas, 76904, United States
Birmingham Clinical Research Unit

Birmingham, Alabama, 35216, United States
Boston Medical Center

Boston, Massachusetts, 02118, United States
Bozeman Health Deaconess Hospital

Bozeman, Montana, 59715, United States
Bozeman Health Deaconess Hospital dba Bozeman Health Clinical Research

Bozeman, Montana, 59715, United States
CEPIC - Centro Paulista de Investigacao Clinica e Servicos Medicos Ltda (Casa Branca)

São Paulo, 04266-010, Brazil
CRS Clinical Research Services Berlin GmbH

Berlin, 13353, Germany
CRS Clinical Research Services Mannheim GmbH

Mannheim, 68167, Germany
California Research Foundation

San Diego, California, 92123, United States
Chinle Comprehensive Health Care Facility

Chinle, Arizona, 86503, United States
Cincinnati Children's Hospital Medical Center

Cincinnati, Ohio, 45229, United States
Clinical Alliance for Research & Education - Infectious Diseases, LLC (CARE-ID)

Annandale, Virginia, 22003, United States
Clinical Neuroscience Solutions, Inc.

Jacksonville, Florida, 32256, United States
Clinical Neuroscience Solutions, Inc.

Memphis, Tennessee, 38119, United States
Clinical Neuroscience Solutions, Inc. dba CNS Healthcare

Orlando, Florida, 32801, United States
Clinical Research Associates, Inc.

Nashville, Tennessee, 37203, United States
Clinical Research Atlanta

Stockbridge, Georgia, 30281, United States
Clinical Research Consulting, LLC

Milford, Connecticut, 06460, United States
Clinical Research Professionals

Chesterfield, Missouri, 63005, United States
Clinical Trials of Texas, Inc.

San Antonio, Texas, 78229, United States
Clinical and Translational Science Center (CTSC) Clinical Research Center (CCRC)

Sacramento, California, 95817, United States
Collaborative Neuroscience Research, LLC

Long Beach, California, 90806, United States
Collaborative Neuroscience Research, LLC. - Investigator Site File Location

Garden Grove, California, 92845, United States
Dayton Clinical Research

Dayton, Ohio, 45406, United States
Dayton Clinical Research

Dayton, Ohio, 45409, United States
DeLand Clinical Research Unit

DeLand, Florida, 32720, United States
Diablo Clinical Research, Inc.

Walnut Creek, California, 94598, United States
Diagnostics Research Group

San Antonio, Texas, 78229, United States
Duke University - Main Hospital and Clinics

Durham, North Carolina, 27703, United States
East-West Medical Research Institute

Honolulu, Hawaii, 96814, United States
Fleming Island Center for Clinical Research

Fleming Island, Florida, 32003, United States
Gallup Indian Medical Center

Gallup, New Mexico, 87301, United States
HOPE Research Institute

Phoenix, Arizona, 85018, United States
HOPE Research Institute

Phoenix, Arizona, 85023, United States
Hacettepe Universitesi Tip Fakultesi

Ankara, 06230, Turkey (Türkiye)
Hany H. Ahmed, MD

Houston, Texas, 77008, United States
Holston Medical Group

Kingsport, Tennessee, 37660, United States
Holston Medical Group-Clinical Research

Bristol, Tennessee, 37620, United States
Hospital Militar Central Cirujano Mayor Dr. Cosme Argerich

CABA, 1426, Argentina
Hospital Santo Antonio/ Associacao Obras Sociais Irma Dulce

Salvador, Estado de Bahia, CEP: 40415-006, Brazil
IACT Health

Columbus, Georgia, 31904, United States
IKF Pneumologie GmbH & Co KG

Frankfurt am Main, 60596, Germany
Icahn School of Medicine at Mount Sinai

New York, New York, 10029, United States
Icahn School of Medicine at Mount Sinai - Investigational Drug Service

New York, New York, 10029, United States
Indago Research & Health Center, Inc

Hialeah, Florida, 33012, United States
Infectious Diseases Physicians, LLC

Annandale, Virginia, 22003, United States
Innovo Research - Austin Regional Clinic

Austin, Texas, 78726, United States
Istanbul Universitesi Istanbul Tip Fakultesi

Istanbul, 34093, Turkey (Türkiye)
Istanbul Universitesi-Cerrahpasa, Cerrahpasa Tip Fakultesi

Istanbul, 34098, Turkey (Türkiye)
Istanbul Yedikule Gogus Hastaliklari ve Gogus Cerrahisi Egitim Arastirma Hastanesi

Istanbul, 34020, Turkey (Türkiye)
J. Lewis Research, Inc. / Foothill Family Clinic

Salt Lake City, Utah, 84109, United States
J. Lewis Research, Inc. / Foothill Family Clinic South

Salt Lake City, Utah, 84121, United States
Jacksonville Center for Clinical Research

Jacksonville, Florida, 32216, United States
Johns Hopkins Bayview Medical Center

Baltimore, Maryland, 21224, United States
Johns Hopkins Center for American Indian Health

Chinle, Arizona, 86503, United States
Johns Hopkins Center for American Indian Health

Whiteriver, Arizona, 85941, United States
Johns Hopkins Center for American Indian Health

Gallup, New Mexico, 87301, United States
Johns Hopkins Center for American Indian Health

Shiprock, New Mexico, 87420, United States
Jongaie Research

Pretoria, Gauteng, 0183, South Africa
Kaiser Permanente Los Angeles Medical Center

Los Angeles, California, 90027, United States
Kaiser Permanente Northwest-Center for Health Research

Portland, Oregon, 97227, United States
Kaiser Permanente Sacramento

Sacramento, California, 95815, United States
Kaiser Permanente Santa Clara

Santa Clara, California, 95051, United States
Kentucky Pediatric/ Adult Research

Bardstown, Kentucky, 40004, United States
Kocaeli Universitesi Tip Fakultesi

Kocaeli, 41380, Turkey (Türkiye)
LSU Health Sciences Center at Shreveport Clinical Trials Office

Shreveport, Louisiana, 71101, United States
LSUHSC-Shreveport

Shreveport, Louisiana, 71103, United States
Lehigh Valley Health Network/Network Office of Research and Innovation

Allentown, Pennsylvania, 18102, United States
Lillestol Research Llc

Fargo, North Dakota, 58104, United States
Limpopo Clinical Research Initiative

Thabazimbi, Limpopo, 0380, South Africa
LinQ Research, LLC

Pearland, Texas, 77584, United States
Long Beach Clinical Trials Services Inc.

Long Beach, California, 90806, United States
Lynn Institute of Denver

Aurora, Colorado, 80012, United States
Lynn Institute of Norman

Norman, Oklahoma, 73072, United States
M3 Wake Research, Inc.

Raleigh, North Carolina, 27612, United States
Main Street Physician's Care

Little River, South Carolina, 29566, United States
Main Street Physician's Care

Loris, South Carolina, 29569, United States
Martin Diagnostic Clinic

Tomball, Texas, 77375, United States
MedPharmics, LLC

Gulfport, Mississippi, 39503, United States
Medical Affiliated Research Center

Huntsville, Alabama, 35801, United States
Medipol Mega Universite Hastanesi

Istanbul, 34214, Turkey (Türkiye)
Medizentrum Essen Borbeck

Essen, 45355, Germany
Meridian Clinical Research

Savannah, Georgia, 31406, United States
Meridian Clinical Research LLC

Binghamton, New York, 13905, United States
Meridian Clinical Research LLC

Vestal, New York, 13850, United States
Meridian Clinical Research LLC

Cincinnati, Ohio, 45246, United States
Meridian Clinical Research, LLC

Omaha, Nebraska, 68134, United States
Meridian Clinical Research, LLC

Binghamton, New York, 13901, United States
Meridian Clinical Research, LLC

Cincinnati, Ohio, 45219, United States
Methodist Physicians Clinic / CCT Research

Fremont, Nebraska, 68025, United States
Michigan Center for Medical Research

Farmington Hills, Michigan, 48334, United States
NYU Langone Health

New York, New York, 10016, United States
National Research Institute

Los Angeles, California, 90057, United States
Newtown Clinical Research Centre

Johannesburg, Gauteng, 2113, South Africa
North Alabama Research Center, LLC

Athens, Alabama, 35611, United States
North Texas Infectious Diseases Consultants, P.A.

Dallas, Texas, 75246, United States
Northern Navajo Medical Center

Shiprock, New Mexico, 87420, United States
Ochsner Clinic Foundation

New Orleans, Louisiana, 70121, United States
Optimal Research

Peoria, Illinois, 61614, United States
Optimal Research, LLC

Huntsville, Alabama, 35802, United States
PMG Research of Charlotte LLC

Charlotte, North Carolina, 28209, United States
PMG Research of Hickory, LLC

Hickory, North Carolina, 28601, United States
PMG Research of Raleigh, LLC

Raleigh, North Carolina, 27609, United States
PMG Research of Raleigh, LLC d/b/a PMG Research of Cary

Cary, North Carolina, 27518, United States
PMG Research of Salisbury, LLC

Salisbury, North Carolina, 28144, United States
PMG Research of Wilmington, LLC

Wilmington, North Carolina, 28401, United States
PMG Research of Winston-Salem, LLC

Winston-Salem, North Carolina, 27103, United States
Paradigm Clinical Research Center

Redding, California, 96001, United States
PharmQuest

Greensboro, North Carolina, 27408, United States
Pharmaron CPC, Inc.

Baltimore, Maryland, 21201, United States
PriMED Clinical Research

Dayton, Ohio, 45429, United States
Quality Clinical Research, Inc.

Omaha, Nebraska, 68114, United States
Research Centers of America

Hollywood, Florida, 33024, United States
Rochester Clinical Research, Inc.

Rochester, New York, 14609, United States
SMS Clinical Research, LLC

Mesquite, Texas, 75149, United States
SUNY Upstate Medical University Global Health Research Unit

Syracuse, New York, 13215, United States
Sakarya Universitesi Egitim ve Arastirma Hastanesi

Sakarya, 54100, Turkey (Türkiye)
Senders Pediatrics

South Euclid, Ohio, 44121, United States
Solaris Clinical Research

Meridian, Idaho, 83646, United States
South Jersey Infectious Disease

Somers Point, New Jersey, 08244, United States
Studienzentrum Brinkum Dr. Lars Pohlmeier und Torsten Drescher

Stuhr, 28816, Germany
Sundance Clinical Research, LLC

St Louis, Missouri, 63141, United States
Tekton Research, Inc.

Austin, Texas, 78745, United States
Texas Center for Drug Development, Inc.

Houston, Texas, 77081, United States
Texas Health Resources

Fort Worth, Texas, 76135, United States
The Pain Center of Arizona

Phoenix, Arizona, 85018, United States
Tiervlei Trial Centre, Basement Level, Karl Bremer Hospital

Cape Town, Western Cape, 7530, South Africa
Trinity Clinical Research

Tullahoma, Tennessee, 37388, United States
UMass Memorial Medical Center - University Campus

Worcester, Massachusetts, 01655, United States
University Hospitals Cleveland Medical Center

Cleveland, Ohio, 44106, United States
University of California Davis Health

Sacramento, California, 95817, United States
University of Iowa Hospitals & Clinics

Iowa City, Iowa, 52242, United States
University of Iowa Hospitals & Clinics Investigational Drug Servces

Iowa City, Iowa, 42242, United States
University of Maryland Medical Center Investigational Drug Service Pharmacy

Baltimore, Maryland, 21201, United States
University of Maryland, Baltimore, Health Sciences Research Facility III

Baltimore, Maryland, 21201, United States
University of Maryland, Center for Vaccine Development and Global Health

Baltimore, Maryland, 21201, United States
University of Rochester Medical Center

Rochester, New York, 14642, United States
University of Rochester Medical Center- Kari Steinmetz

Rochester, New York, 14642, United States
University of Texas Medical Branch

Galveston, Texas, 77555, United States
Universitätsklinikum Hamburg-Eppendorf

Hamburg, 20359, Germany
VA Northeast Ohio Healthcare System

Cleveland, Ohio, 44106, United States
Velocity Clinical Research, Inc.

Cleveland, Ohio, 44122, United States
Velocity Clinical Research, Norfolk

Sioux City, Iowa, 51106, United States
Velocity Clinical Research, Norfolk

Norfolk, Nebraska, 68701, United States
Velocity Clinical Research, North Hollywood

North Hollywood, California, 91606, United States
Velocity Clinical Research, Providence

East Greenwich, Rhode Island, 02818, United States
Velocity Clinical Research, Washington DC

Savannah, Georgia, 31406, United States
Ventavia Research Group, LLC

Fort Worth, Texas, 76104, United States
Ventavia Research Group, LLC

Houston, Texas, 77008, United States
Ventavia Research Group, LLC

Keller, Texas, 76248, United States
Virginia Research Center LLC

Midlothian, Virginia, 23114, United States
Wake Research-Clinical Research Center of Nevada, LLC

Las Vegas, Nevada, 89106, United States
Wenatchee Valley Hospital

Wenatchee, Washington, 98801, United States
Whiteriver Indian Hospital

Whiteriver, Arizona, 85941, United States
Whiteriver Indian Hospital - Garrett Building

Whiteriver, Arizona, 85941, United States
Yale Center for Clinical Investigations (CSRU)

New Haven, Connecticut, 06519, United States
Yale University

New Haven, Connecticut, 06510, United States

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