The study will evaluate the safety, tolerability, and efficacy of a booster dose of BNT162b2 when administered to participants having previously received 2 doses of BNT162b2 at least 6 months prior to randomization. The study is designed to describe vaccine efficacy of a booster dose of BNT162b2 over time against COVID-19 - At a dose of 30µg (as studied in the Phase 2/3 study C4591001) - In healthy adults 16 years of age and older - The duration of the study for each participant will be up to approximately 12 months. - The study will be conducted in the United States, Brazil and South Africa



Eligible Ages
Over 16 Years
Eligible Genders
Accepts Healthy Volunteers

Inclusion Criteria

  • Male or female participants ≥16 years of age at Visit 1 (Day 1) who participated in C4591001. - 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 (if required), and clinical judgment of the investigator to be eligible for inclusion in the study. - Capable of giving signed informed consent. - Participants who have received 2 prior doses of 30 µg BNT162b2 19-42 days apart, with the second dose being at least 175 days before Visit 1 (Day 1).

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. - History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the study intervention. - 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. - Immunocompromised individuals with known or suspected immunodeficiency, as determined by history and/or laboratory/physical examination. - 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. - Individuals who receive treatment with radiotherapy or immunosuppressive therapy, including cytotoxic agents or systemic corticosteroids, eg, for cancer or an autoimmune disease, or planned receipt throughout the study. - Receipt of blood/plasma products, immunoglobulin, or monoclonal antibodies, from 60 days before study intervention administration, or receipt of any passive antibody therapy specific to COVID-19, from 90 days before study intervention administration, or planned receipt throughout the study. - Prior receipt of any COVID-19 vaccine other than BNT162b2. - Investigator site staff or Pfizer/BioNTech employees directly involved in the conduct of the study, site staff otherwise supervised by the investigator, and their respective family members. - Receipt of medications intended to prevent COVID-19. - Prior receipt of more than 2 doses of BNT162b2 30 µg. - Participation in other studies involving study intervention within 28 days prior to study entry, other than C4591001, and/or during study participation.

Study Design

Phase 3
Study Type
Intervention Model
Parallel Assignment
Primary Purpose
Triple (Participant, Care Provider, Investigator)

Arm Groups

ArmDescriptionAssigned Intervention
1 dose
  • Biological: BNT162b2
    Intramuscular Injection
Placebo Comparator
1 dose
  • Other: Placebo
    Intramuscular Injection

Recruiting Locations

Boston Medical Center
Boston, Massachusetts 02118

More Details

BioNTech SE

Study Contact

Pfizer CT.gov Call Center


Study information shown on this site is derived from ClinicalTrials.gov (a public registry operated by the National Institutes of Health). The listing of studies provided is not certain to be all studies for which you might be eligible. Furthermore, study eligibility requirements can be difficult to understand and may change over time, so it is wise to speak with your medical care provider and individual research study teams when making decisions related to participation.