All Parts - Percentage of Participants Reporting Adverse Events (AEs);All Parts - Percentage of Participants Reporting Local Reactions at the Injection Site (Pain, Tenderness, Erythema/Redness, Induration/Swelling);All Parts - Percentage of Participants Reporting Serious Adverse Events (SAEs);All Parts - Percentage of Participants Reporting Systemic Events (Fever, Fatigue, Headache, Chills, Vomiting, Nausea, Diarrhea, New or Worsened Muscle Pain, and New or Worsened Joint Pain);Part B - Difference in Seroresponse (SR) to B.1.1.7 NT 1 Month After 1 Dose of BNT162b2 (B.1.1.7 + B.1.617.2) in BNT162b2-experienced Participants to the Reference Strain NT 1 Month After 2 Doses of BNT162b2 in Participants From C4591001 (NCT04368728);Part B - Difference in SR to B.1.617.2 NT 1 Month After 1 Dose of BNT162b2 (B.1.1.7 + B.1.617.2) in BNT162b2-experienced Participants to the Reference Strain NT 1 Month After 2 Doses of BNT162b2 in Participants From C4591001 (NCT04368728);Part B - Difference in SR to B.1.617.2 NT 1 Month After 1 Dose of BNT162b2 (B.1.617.2) in BNT162b2-experienced Participants to the Reference Strain NT 1 Month After 2 Doses of BNT162b2 in Participants From C4591001 (NCT04368728);Part B - GMR of B.1.1.7 NT 1 Month After 1 Dose of BNT162b2 (B.1.1.7 + B.1.617.2) in BNT162b2-experienced Participants to the Reference Strain NT 1 Month After 2 Doses of BNT162b2 in Participants From the Phase III C4591001 (NCT04368728) Trial;Part B - GMR of B.1.1.7 NT 1 Month After 2 Doses of BNT162b2 (B.1.1.7 + B.1.617.2) in COVID-19 Vaccine-naïve Participants to the Reference Strain NT 1 Month After 2 Doses of BNT162b2 in Participants From the C4591001 (NCT04368728) Trial;Part B - GMR of B.1.617.2 NT 1 Month After 1 Dose of BNT162b2 (B.1.1.7 + B.1.617.2) in BNT162b2-experienced Participants to the Reference Strain NT 1 Month After 2 Doses of BNT162b2 in Participants From the Phase III C4591001 (NCT04368728) Trial;Part B - GMR of B.1.617.2 NT 1 Month After 1 Dose of BNT162b2 (B.1.617.2) in BNT162b2-experienced Participants to the Reference Strain NT 1 Month After 2 Doses of BNT162b2 in Participants From the Phase III C4591001 (NCT04368728) Trial;Part B - GMR of B.1.617.2 NT 1 Month After 2 Doses of BNT162b2 (B.1.1.7 + B.1.617.2) in COVID-19 Vaccine-naïve Participants to the Reference Strain NT 1 Month After 2 Doses of BNT162b2 in Participants From the C4591001 (NCT04368728) Trial;Part B - GMR of Reference Strain NT After One Dose of BNT162b2 (B.1.1.7 + B.1.617.2) in Participants With Evidence of Prior Infection to the Reference Strain NT After 2 Doses of BNT162b2 in Participants Without Evidence of Infection;Part B - The Difference in SRs to the Reference Strain NT in Subjects With Evidence of Prior Infection and to the Reference Strain NT in Participants Without Evidence of Infection (COVID-19 Vaccine-naïve Participants);Part B - The Difference in SR to B.1.1.7 NT 1 Month After 2 Doses of BNT162b2 (B.1.1.7 + B.1.617.2) in COVID-19 Vaccine-naïve Participants to the Reference Strain NT 1 Month After 2 Doses of BNT162b2 in Participants From the C4591001 (NCT04368728) Trial;Part B - The Difference in SR to B.1.617.2 NT 1 Month After 2 Doses of BNT162b2 (B.1.1.7 + B.1.617.2) in COVID-19 Vaccine-naïve Participants to the Reference Strain NT 1 Month After 2 Doses of BNT162b2 in Participants From the C4591001 (NCT04368728) Trial;Part C - GMR of B.1.1.529.1 NT 1 Month After One Dose of BNT162b2 (B.1.1.529.1) in RNA-based COVID-19 Vaccine-experienced Participants With History of SARS-CoV-2 Infection to Those at 1 Month After One Dose of BNT162b2 for Cohorts 7 and 8.;Part C - The Difference in SR of B.1.1.529.1 NT 1 Month After One Dose of BNT162b2 (B.1.1.529.1) in RNA-based COVID-19 Vaccine-experienced Participants With History of SARS-CoV-2 Infection to Those at 1 Month After One Dose of BNT162b2 for Cohorts 7 & 8.

All Parts - Percentage of Participants Reporting Adverse Events (AEs);All Parts - Percentage of Participants Reporting Local Reactions at the Injection Site (Pain, Tenderness, Erythema/Redness, Induration/Swelling);All Parts - Percentage of Participants Reporting Serious Adverse Events (SAEs);All Parts - Percentage of Participants Reporting Systemic Events (Fever, Fatigue, Headache, Chills, Vomiting, Nausea, Diarrhea, New or Worsened Muscle Pain, and New or Worsened Joint Pain);Part B - Difference in Seroresponse (SR) to B.1.1.7 NT 1 Month After 1 Dose of BNT162b2 (B.1.1.7 + B.1.617.2) in BNT162b2-experienced Participants to the Reference Strain NT 1 Month After 2 Doses of BNT162b2 in Participants From C4591001 (NCT04368728);Part B - Difference in SR to B.1.617.2 NT 1 Month After 1 Dose of BNT162b2 (B.1.1.7 + B.1.617.2) in BNT162b2-experienced Participants to the Reference Strain NT 1 Month After 2 Doses of BNT162b2 in Participants From C4591001 (NCT04368728);Part B - Difference in SR to B.1.617.2 NT 1 Month After 1 Dose of BNT162b2 (B.1.617.2) in BNT162b2-experienced Participants to the Reference Strain NT 1 Month After 2 Doses of BNT162b2 in Participants From C4591001 (NCT04368728);Part B - GMR of B.1.1.7 NT 1 Month After 1 Dose of BNT162b2 (B.1.1.7 + B.1.617.2) in BNT162b2-experienced Participants to the Reference Strain NT 1 Month After 2 Doses of BNT162b2 in Participants From the Phase III C4591001 (NCT04368728) Trial;Part B - GMR of B.1.1.7 NT 1 Month After 2 Doses of BNT162b2 (B.1.1.7 + B.1.617.2) in COVID-19 Vaccine-naïve Participants to the Reference Strain NT 1 Month After 2 Doses of BNT162b2 in Participants From the C4591001 (NCT04368728) Trial;Part B - GMR of B.1.617.2 NT 1 Month After 1 Dose of BNT162b2 (B.1.1.7 + B.1.617.2) in BNT162b2-experienced Participants to the Reference Strain NT 1 Month After 2 Doses of BNT162b2 in Participants From the Phase III C4591001 (NCT04368728) Trial;Part B - GMR of B.1.617.2 NT 1 Month After 1 Dose of BNT162b2 (B.1.617.2) in BNT162b2-experienced Participants to the Reference Strain NT 1 Month After 2 Doses of BNT162b2 in Participants From the Phase III C4591001 (NCT04368728) Trial;Part B - GMR of B.1.617.2 NT 1 Month After 2 Doses of BNT162b2 (B.1.1.7 + B.1.617.2) in COVID-19 Vaccine-naïve Participants to the Reference Strain NT 1 Month After 2 Doses of BNT162b2 in Participants From the C4591001 (NCT04368728) Trial;Part B - GMR of Reference Strain NT After One Dose of BNT162b2 (B.1.1.7 + B.1.617.2) in Participants With Evidence of Prior Infection to the Reference Strain NT After 2 Doses of BNT162b2 in Participants Without Evidence of Infection;Part B - The Difference in SRs to the Reference Strain NT in Subjects With Evidence of Prior Infection and to the Reference Strain NT in Participants Without Evidence of Infection (COVID-19 Vaccine-naïve Participants);Part B - The Difference in SR to B.1.1.7 NT 1 Month After 2 Doses of BNT162b2 (B.1.1.7 + B.1.617.2) in COVID-19 Vaccine-naïve Participants to the Reference Strain NT 1 Month After 2 Doses of BNT162b2 in Participants From the C4591001 (NCT04368728) Trial;Part B - The Difference in SR to B.1.617.2 NT 1 Month After 2 Doses of BNT162b2 (B.1.1.7 + B.1.617.2) in COVID-19 Vaccine-naïve Participants to the Reference Strain NT 1 Month After 2 Doses of BNT162b2 in Participants From the C4591001 (NCT04368728) Trial;Part C - GMR of B.1.1.529.1 NT 1 Month After One Dose of BNT162b2 (B.1.1.529.1) in RNA-based COVID-19 Vaccine-experienced Participants With History of SARS-CoV-2 Infection to Those at 1 Month After One Dose of BNT162b2 for Cohorts 7 and 8.;Part C - The Difference in SR of B.1.1.529.1 NT 1 Month After One Dose of BNT162b2 (B.1.1.529.1) in RNA-based COVID-19 Vaccine-experienced Participants With History of SARS-CoV-2 Infection to Those at 1 Month After One Dose of BNT162b2 for Cohorts 7 & 8.

All parts - Percentage of participants reporting adverse events (AEs);All parts - Percentage of participants reporting local reactions at the injection site;All parts - Percentage of participants reporting serious adverse events (SAEs);All parts - Percentage of participants reporting systemic events;Part B - GMR of B.1.1.7 NT 1 month after 1 dose of BNT162b2 (B.1.1.7 + B.1.617.2) in BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III C4591001 trial.;Part B - GMR of B.1.1.7 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) in COVID-19 vaccine-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) in COVID-19 vaccine-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of reference strain NT in participants with evidence of prior infection to the reference strain NT in participants without evidence of infection (COVID-19 vaccine-naïve participants);Part B - The difference in Seroresponse (SR) to B.1.1.7;Part B - The difference in SRs to the reference strain NT in subjects with evidence of prior infection and to the reference strain NT in participants without evidence of infection (COVID-19 vaccine-naïve participants);Part B - The difference in SR to B.1.1.7 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) in COVID-19 vaccine-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III C4591001 trial;Part B - The difference in SR to B.1.617.2;Part B - The difference in SR to B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - The difference in SR to B.1.617.2 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) in COVID-19 vaccine-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III C4591001 trial;Part C - GMR of B.1.1.529.1 NT 1 month after one dose of BNT162b2 (B.1.1.529.1) in RNA-based COVID-19 vaccine-experienced participants with history of SARS-CoV-2 infection to those at 1 month after one dose of BNT162b2 for Cohorts 7 and 8.;Part C - The difference in SR of B.1.1.529.1 NT 1 month after one dose of BNT162b2 (B.1.1.529.1) in RNA-based COVID-19 vaccine-experienced participants with history of SARS-CoV-2 infection to those at 1 month after one dose of BNT162b2 for Cohorts 7 & 8.

All parts - Percentage of participants reporting adverse events (AEs);All parts - Percentage of participants reporting local reactions at the injection site;All parts - Percentage of participants reporting serious adverse events (SAEs);All parts - Percentage of participants reporting systemic events;Part B - GMR of B.1.1.7 NT 1 month after 1 dose of BNT162b2 (B.1.1.7 + B.1.617.2) in BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III C4591001 trial.;Part B - GMR of B.1.1.7 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) in COVID-19 vaccine-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) in COVID-19 vaccine-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of reference strain NT in participants with evidence of prior infection to the reference strain NT in participants without evidence of infection (COVID-19 vaccine-naïve participants);Part B - The difference in Seroresponse (SR) to B.1.1.7;Part B - The difference in SRs to the reference strain NT in subjects with evidence of prior infection and to the reference strain NT in participants without evidence of infection (COVID-19 vaccine-naïve participants);Part B - The difference in SR to B.1.1.7 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) in COVID-19 vaccine-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III C4591001 trial;Part B - The difference in SR to B.1.617.2;Part B - The difference in SR to B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - The difference in SR to B.1.617.2 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) in COVID-19 vaccine-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III C4591001 trial;Part C - GMR of B.1.1.529.1 NT 1 month after one dose of BNT162b2 (B.1.1.529.1) in RNA-based COVID-19 vaccine-experienced participants with history of SARS-CoV-2 infection to those at 1 month after one dose of BNT162b2 for Cohorts 7 and 8.;Part C - The difference in SR of B.1.1.529.1 NT 1 month after one dose of BNT162b2 (B.1.1.529.1) in RNA-based COVID-19 vaccine-experienced participants with history of SARS-CoV-2 infection to those at 1 month after one dose of BNT162b2 for Cohorts 7 & 8.

All parts - Percentage of participants reporting local reactions at the injection site;All parts - Percentage of participants reporting serious adverse events (SAEs);All parts - Percentage of participants reporting systemic events;Part A and C - Percentage of participants reporting adverse events (AEs);Part B - Geometric mean ratio (GMR) of B.1.1.7;Part B - GMR of B.1.1.7 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - Percentage of participants reporting adverse events (AEs);Part B - The difference in Seroresponse (SR) to B.1.1.7;Part B - The difference in SR to B.1.1.7 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - The difference in SR to B.1.617.2;Part B - The difference in SR to B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - The difference in SR to B.1.617.2 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02/C4591001 trial;Part C - GMR of B.1.1.529 NT 1 month after one dose of BNT162b2 (B.1.1.529) in RNA-based COVID-19 vaccine-experienced participants with history of SARS-CoV-2 infection to those at 1 month after one dose of BNT162b2 for Cohorts 7 and 8.;Part C - The difference in SR of B.1.1.529 NT 1 month after one dose of BNT162b2 (B.1.1.529) in RNA-based COVID-19 vaccine-experienced participants with history of SARS-CoV-2 infection to those at 1 month after one dose of BNT162b2 for Cohorts 7 and 8.

All parts - Percentage of participants reporting local reactions at the injection site;All parts - Percentage of participants reporting serious adverse events (SAEs);All parts - Percentage of participants reporting systemic events;Part A and C - Percentage of participants reporting adverse events (AEs);Part B - Geometric mean ratio (GMR) of B.1.1.7;Part B - GMR of B.1.1.7 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - Percentage of participants reporting adverse events (AEs);Part B - The difference in Seroresponse (SR) to B.1.1.7;Part B - The difference in SR to B.1.1.7 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - The difference in SR to B.1.617.2;Part B - The difference in SR to B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - The difference in SR to B.1.617.2 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02/C4591001 trial;Part C - GMR of B.1.1.529 NT 1 month after one dose of BNT162b2 (B.1.1.529) in RNA-based COVID-19 vaccine-experienced participants with history of SARS-CoV-2 infection to those at 1 month after one dose of BNT162b2 for Cohorts 7 and 8.;Part C - The difference in SR of B.1.1.529 NT 1 month after one dose of BNT162b2 (B.1.1.529) in RNA-based COVID-19 vaccine-experienced participants with history of SARS-CoV-2 infection to those at 1 month after one dose of BNT162b2 for Cohorts 7 and 8.

Part B - Geometric mean ratio (GMR) of B.1.1.7;Part B - GMR of B.1.1.7 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - The difference in Seroresponse (SR) to B.1.1.7;Part B - The difference in SR to B.1.1.7 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - The difference in SR to B.1.617.2;Part B - The difference in SR to B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - The difference in SR to B.1.617.2 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02/C4591001 trial;Part C - GMR of B.1.1.529 NT 1 month after one dose of BNT162b2 (B.1.1.529) in RNA-based COVID-19 vaccine-experienced participants with history of SARS-CoV-2 infection to those at 1 month after one dose of BNT162b2 for Cohorts 7 and 8.;Part C - The difference in SR of B.1.1.529 NT 1 month after one dose of BNT162b2 (B.1.1.529) in RNA-based COVID-19 vaccine-experienced participants with history of SARS-CoV-2 infection to those at 1 month after one dose of BNT162b2 for Cohorts 7 and 8.;Percentage of participants reporting adverse events (AEs);Percentage of participants reporting local reactions at the injection site;Percentage of participants reporting serious adverse events (SAEs);Percentage of participants reporting systemic events

Part B - Geometric mean ratio (GMR) of B.1.1.7;Part B - GMR of B.1.1.7 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - The difference in Seroresponse (SR) to B.1.1.7;Part B - The difference in SR to B.1.1.7 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - The difference in SR to B.1.617.2;Part B - The difference in SR to B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - The difference in SR to B.1.617.2 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02/C4591001 trial;Part C - GMR of B.1.1.529 NT 1 month after one dose of BNT162b2 (B.1.1.529) in RNA-based COVID-19 vaccine-experienced participants with history of SARS-CoV-2 infection to those at 1 month after one dose of BNT162b2 for Cohorts 7 and 8.;Part C - The difference in SR of B.1.1.529 NT 1 month after one dose of BNT162b2 (B.1.1.529) in RNA-based COVID-19 vaccine-experienced participants with history of SARS-CoV-2 infection to those at 1 month after one dose of BNT162b2 for Cohorts 7 and 8.;Percentage of participants reporting adverse events (AEs);Percentage of participants reporting local reactions at the injection site;Percentage of participants reporting serious adverse events (SAEs);Percentage of participants reporting systemic events

Part B - Geometric mean ratio (GMR) of B.1.1.7;Part B - GMR of B.1.1.7 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - The difference in Seroresponse (SR) to B.1.1.7;Part B - The difference in SR to B.1.1.7 NT 1 month after 1 dose of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - The difference in SR to B.1.617.2;Part B - The difference in SR to B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - The difference in SR to B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Percentage of participants reporting adverse events (AEs);Percentage of participants reporting local reactions at the injection site;Percentage of participants reporting serious adverse events (SAEs);Percentage of participants reporting systemic events

Part B - Geometric mean ratio (GMR) of B.1.1.7;Part B - GMR of B.1.1.7 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - GMR of B.1.617.2 NT 1 month after 2 doses of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - The difference in Seroresponse (SR) to B.1.1.7;Part B - The difference in SR to B.1.1.7 NT 1 month after 1 dose of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - The difference in SR to B.1.617.2;Part B - The difference in SR to B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.1.7 + B.1.617.2) on BNT162b2-naïve participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Part B - The difference in SR to B.1.617.2 NT 1 month after 1 dose of BNT162b2 (B.1.617.2) on BNT162b2-experienced participants to the reference strain NT 1 month after 2 doses of BNT162b2 in participants from the Phase III BNT162-02 / C4591001 trial;Percentage of participants reporting adverse events (AEs);Percentage of participants reporting local reactions at the injection site;Percentage of participants reporting serious adverse events (SAEs);Percentage of participants reporting systemic events