- 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. - known infection with hiv, hcv, or hbv. - 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. - primary study: previous vaccination with any coronavirus vaccine. - booster study: previous vaccination with any coronavirus vaccine outside of this study. - receipt of medications intended to prevent covid-19. - 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 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 and/or during study participation. - previous participation in other studies involving study intervention containing lipid nanoparticles. - 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. additional exclusion criteria for the booster study: - current febrile illness (body temperature ≥100.4°f [≥38.0°c]) or other acute illness within 48 hours before study intervention administration. - receipt of any seasonal or pandemic influenza vaccine within 14 days, or any other nonstudy vaccine within 28 days, before or after study intervention administration. - receipt of short-term (<14 days) systemic corticosteroids. inhaled/nebulized, intra-articular, intrabursal, or topical (skin or eyes) corticosteroids are permitted.

- 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. - known infection with hiv, hcv, or hbv. - 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. - primary study: previous vaccination with any coronavirus vaccine. - booster study: previous vaccination with any coronavirus vaccine outside of this study. - receipt of medications intended to prevent covid-19. - 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 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 and/or during study participation. - previous participation in other studies involving study intervention containing lipid nanoparticles. - 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. additional exclusion criteria for the booster study: - current febrile illness (body temperature ≥100.4°f [≥38.0°c]) or other acute illness within 48 hours before study intervention administration. - receipt of any seasonal or pandemic influenza vaccine within 14 days, or any other nonstudy vaccine within 28 days, before or after study intervention administration. - receipt of short-term (<14 days) systemic corticosteroids. inhaled/nebulized, intra-articular, intrabursal, or topical (skin or eyes) corticosteroids are permitted.

- 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. - known infection with hiv, hcv, or hbv. - 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. - previous vaccination with any coronavirus vaccine. - receipt of medications intended to prevent covid-19. - 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 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 and/or during study participation. - previous participation in other studies involving study intervention containing lipid nanoparticles. - 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.

- 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. - known infection with hiv, hcv, or hbv. - 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. - previous vaccination with any coronavirus vaccine. - receipt of medications intended to prevent covid-19. - 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 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 and/or during study participation. - previous participation in other studies involving study intervention containing lipid nanoparticles. - 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.

- 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. - known infection with hiv, hcv, or hbv. - 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. - 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. - receipt of medications intended to prevent covid-19. - 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 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 and/or during study participation. - previous participation in other studies involving study intervention containing lipid nanoparticles. - 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.

- 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. - known infection with hiv, hcv, or hbv. - 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. - 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. - receipt of medications intended to prevent covid-19. - 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 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 and/or during study participation. - previous participation in other studies involving study intervention containing lipid nanoparticles. - 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.