Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status With Onset at Least 14 Days After Double-blind Vaccination on Day 1 (Day 15): Double-blind Phase;Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical COVID-19 With Seronegative Status With Onset at Least 28 Days After Double-blind Vaccination on Day 1 (Day 29): Double-blind Phase;Number of Participants With Solicited Local Adverse Events (AEs) Up to 7 Days After Booster Vaccination (Open-label Booster Vaccination Phase);Number of Participants With Solicited Systemic AEs Up to 7 Days After Booster Vaccination (Open-label Booster Vaccination Phase);Number of Participants With Unsolicited AEs Up to 28 Days After Booster Vaccination (Open-label Booster Vaccination Phase)

Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status With Onset at Least 14 Days After Double-blind Vaccination on Day 1 (Day 15): Double-blind Phase;Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical COVID-19 With Seronegative Status With Onset at Least 28 Days After Double-blind Vaccination on Day 1 (Day 29): Double-blind Phase;Number of Participants With Solicited Local Adverse Events (AEs) Up to 7 Days After Booster Vaccination (Open-label Booster Vaccination Phase);Number of Participants With Solicited Systemic AEs Up to 7 Days After Booster Vaccination (Open-label Booster Vaccination Phase);Number of Participants With Unsolicited AEs Up to 28 Days After Booster Vaccination (Open-label Booster Vaccination Phase)

Number of Participants With Adverse Events of Special Interest (AESI) From Booster Vaccination Until End of the Study (Open-label Booster Vaccination Phase);Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Main Study);Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical COVID-19 With Seronegative Status (Main Study);Number of Participants With First Occurrence of Molecularly Confirmed Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants With First Occurrence of Molecularly Confirmed Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants With Serious Adverse Events (SAEs) From Booster Vaccination Until End of the Study (Open-label Booster Vaccination Phase);Number of Participants With Solicited Local Adverse Events (AEs) Up to 7 Days After Booster Vaccination (Open-label Booster Vaccination Phase);Number of Participants With Solicited Systemic AEs Up to 7 Days After Booster Vaccination (Open-label Booster Vaccination Phase);Number of Participants With Unsolicited AEs Up to 28 Days After Booster Vaccination (Open-label Booster Vaccination Phase)

Number of Participants With Adverse Events of Special Interest (AESI) From Booster Vaccination Until End of the Study (Open-label Booster Vaccination Phase);Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Main Study);Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical COVID-19 With Seronegative Status (Main Study);Number of Participants With First Occurrence of Molecularly Confirmed Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants With First Occurrence of Molecularly Confirmed Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants With Serious Adverse Events (SAEs) From Booster Vaccination Until End of the Study (Open-label Booster Vaccination Phase);Number of Participants With Solicited Local Adverse Events (AEs) Up to 7 Days After Booster Vaccination (Open-label Booster Vaccination Phase);Number of Participants With Solicited Systemic AEs Up to 7 Days After Booster Vaccination (Open-label Booster Vaccination Phase);Number of Participants With Unsolicited AEs Up to 28 Days After Booster Vaccination (Open-label Booster Vaccination Phase)

None

Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Main Study) [ Time Frame: 14 Days after double-blind vaccination (Day 15) ] Molecularly confirmed moderate to severe/critical COVID-19 was defined as a severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) positive reverse transcription-polymerase chain reaction (RT-PCR) or molecular test result from any available respiratory tract sample (example, nasal swab sample, sputum sample, throat swab sample, saliva sample) or other sample. Moderate included one sign or symptom such as respiratory rate >= 20 breaths per minute and symptoms such as shortness of breath or two signs or symptoms such as heart rate >= 90 beats per minute (beats/minute) and symptoms such as cough from a list of signs and symptoms and severe/critical included one of the following signs and symptoms: respiratory rate >=30 breaths/minute, heart rate >=125 beats/minute, oxygen saturation (SpO2) <= 93% on room air at sea level respiratory failure, evidence of shock, significant acute renal, hepatic, or neurologic dysfunction, admission to the ICU, death defined as per FDA guidance. Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical COVID-19 With Seronegative Status (Main Study) [ Time Frame: 28 Days after double-blind vaccination (Day 29) ] Molecularly confirmed moderate to severe/critical COVID-19 was defined as a SARS-CoV-2 positive RT-PCR or molecular test result from any available respiratory tract sample (example, nasal swab sample, sputum sample, throat swab sample, saliva sample) or other sample. Moderate included one sign or symptom such as respiratory rate >=20 breaths per minute and symptoms such as shortness of breath or two signs or symptoms such as heart rate >= 90 beats/minute and symptoms such as cough from a list of signs and symptoms and severe/critical included one of the following signs and symptoms: respiratory rate >=30 breaths/minute, heart rate >=125 beats/minute, SpO2 less than or equal to (<=) 93 percent (%) on room air at sea level respiratory failure, evidence of shock, significant acute renal, hepatic, or neurologic dysfunction, admission to the Intensive Care Unit (ICU), death defined as per Food and Drug Administration (FDA) guidance. Number of Participants With Solicited Local Adverse Events (AEs) Up to 7 Days After Booster Vaccination (Open-label Booster Vaccination Phase) [ Time Frame: Up to Day 372 (7 Days after booster vaccination on Day 365 [Year 1]) ] Participants who receive the booster dose was asked to note in the e-Diary occurrences of injection site pain/tenderness, erythema, and swelling at the study vaccine injection site daily for 7 days post-booster vaccination (day of vaccination and the subsequent 7 days). Number of Participants With Solicited Systemic AEs Up to 7 Days After Booster Vaccination (Open-label Booster Vaccination Phase) [ Time Frame: Up to Day 372 (7 Days after booster vaccination on Day 365 [Year 1]) ] Participants recorded the temperature in the e-Diary in the evening of the day of vaccination, and then daily for the next 7 days approximately at the same time each day. If more than 1 measurement was made on any given day, the highest temperature of that day was recorded in the e-Diary. Fever was defined as endogenous elevation of body temperature >= 38.0 degree Celsius or >=100.4-degree Fahrenheit, as recorded in at least 1 measurement. Participants also noted the signs and symptoms in the e-Diary on a daily basis for 7 days post-booster vaccination (day of vaccination and the subsequent 7 days), if feasible, for the following events: fatigue, headache, nausea, myalgia. Number of Participants With Unsolicited AEs Up to 28 Days After Booster Vaccination (Open-label Booster Vaccination Phase) [ Time Frame: Up to Day 393 (28 Days after booster vaccination on Day 365 [Year 1]) ] Unsolicited AEs were all AEs for which the participant is not specifically questioned in the participant diary. Number of Participants With Serious Adverse Events (SAEs) From Booster Vaccination Until End of the Study (Open-label Booster Vaccination Phase) [ Time Frame: From booster vaccination (Year 1) up to end of the study (up to 2 years 3 months) ] SAE is any untoward medical occurrence that at any dose may result in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, is a suspected transmission of any infectious agent via a medicinal product. Number of Participants With Adverse Events of Special Interest (AESI) From Booster Vaccination Until End of the Study (Open-label Booster Vaccination Phase) [ Time Frame: From booster vaccination (Year 1) up to end of the study (up to 2 years 3 months) ] Number of participants with AESIs were reported. AESIs are significant AEs that are judged to be of special interest because of clinical importance, known or suspected class effects, or based on nonclinical signals. Thrombosis with Thrombocytopenia Syndrome (TTS), a syndrome characterized by a combination of both a thrombotic event and thrombocytopenia, is considered to be an AESI in this study. A suspected TTS case is defined as: Thrombotic events: suspected deep vessel venous or arterial thrombotic events; Thrombocytopenia, defined as platelet count below 150,000/micro liter. Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Open-label Booster Vaccination Phase) [ Time Frame: 14 Days after unblinding visit to 1 year follow up of the last booster vaccination (up to Day 546) ] Molecularly confirmed moderate to severe/critical COVID-19 was defined as a SARS-CoV-2 positive RT-PCR or molecular test result from any available respiratory tract sample (example, nasal swab sample, sputum sample, throat swab sample, saliva sample) or other sample. Moderate included one sign or symptom such as respiratory rate >= 20 breaths per minute and symptoms such as shortness of breath or two signs or symptoms such as heart rate >= 90 beats per minute (beats/minute) and symptoms such as cough from a list of signs and symptoms and severe/critical included one of the following signs and symptoms: respiratory rate >=30 breaths/minute, heart rate >=125 beats/minute,SpO2 <=93% on room air at sea level respiratory failure, evidence of shock, significant acute renal, hepatic, or neurologic dysfunction, admission to the ICU, death defined as per FDA guidance. Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Open-label Booster Vaccination Phase) [ Time Frame: 28 Days after unblinding visit to 1 year follow up of the last booster vaccination (up to Day 560) ] Molecularly confirmed moderate to severe/critical COVID-19 was defined as a SARS-CoV-2 positive RT-PCR or molecular test result from any available respiratory tract sample (example, nasal swab sample, sputum sample, throat swab sample, saliva sample) or other sample. Moderate included one sign or symptom such as respiratory rate >= 20 breaths per minute and symptoms such as shortness of breath or two signs or symptoms such as heart rate >= 90 beats per minute (beats/minute) and symptoms such as cough from a list of signs and symptoms and severe/critical included one of the following signs and symptoms: respiratory rate >=30 breaths/minute, heart rate >=125 beats/minute,SpO2 <=93% on room air at sea level respiratory failure, evidence of shock, significant acute renal, hepatic, or neurologic dysfunction, admission to the ICU, death defined as per FDA guidance. Number of Participants With First Occurrence of Molecularly Confirmed Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Open-label Booster Vaccination Phase) [ Time Frame: 14 days after booster vaccination (Day 379) to end of study (up to 2 years and 3 month) ] Severe/critical COVID-19 was defined as a SARS-CoV-2 positive RT-PCR or molecular test result from any available respiratory tract sample (example, nasal swab sample, sputum sample, throat swab sample, saliva sample) or other sample and one of the following signs and symptoms: respiratory rate >=30 breaths/minute, heart rate >=125 beats/minute,SpO2 <=93% on room air at sea level respiratory failure, evidence of shock, significant acute renal, hepatic, or neurologic dysfunction, admission to the ICU, death defined as per FDA guidance. Number of Participants With First Occurrence of Molecularly Confirmed Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Open-label Booster Vaccination Phase) [ Time Frame: 28 days after booster vaccination (Day 393) to end of study (up to 2 years and 3 month) ] Severe/critical COVID-19 was defined as a SARS-CoV-2 positive RT-PCR or molecular test result from any available respiratory tract sample (example, nasal swab sample, sputum sample, throat swab sample, saliva sample) or other sample and one of the following signs and symptoms: respiratory rate >=30 breaths/minute, heart rate >=125 beats/minute,SpO2 <=93% on room air at sea level respiratory failure, evidence of shock, significant acute renal, hepatic, or neurologic dysfunction, admission to the ICU, death defined as per FDA guidance.

Number of Participants With Adverse Events of Special Interest (AESI) From Booster Vaccination Until End of the Study (Open-label Booster Vaccination Phase);Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Main Study);Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical COVID-19 With Seronegative Status (Main Study);Number of Participants With First Occurrence of Molecularly Confirmed Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants With First Occurrence of Molecularly Confirmed Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants With Serious Adverse Events (SAEs) From Booster Vaccination Until End of the Study (Open-label Booster Vaccination Phase);Number of Participants With Solicited Local Adverse Events (AEs) Up to 7 Days After Booster Vaccination (Open-label Booster Vaccination Phase);Number of Participants With Solicited Systemic AEs Up to 7 Days After Booster Vaccination (Open-label Booster Vaccination Phase);Number of Participants With Unsolicited AEs Up to 28 Days After Booster Vaccination (Open-label Booster Vaccination Phase)

Number of Participants With Adverse Events of Special Interest (AESI) From Booster Vaccination Until End of the Study (Open-label Booster Vaccination Phase);Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Main Study);Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants With First Occurrence of Molecularly Confirmed Moderate to Severe/Critical COVID-19 With Seronegative Status (Main Study);Number of Participants With First Occurrence of Molecularly Confirmed Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants With First Occurrence of Molecularly Confirmed Severe/Critical Coronavirus Disease (COVID-19) With Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants With Serious Adverse Events (SAEs) From Booster Vaccination Until End of the Study (Open-label Booster Vaccination Phase);Number of Participants With Solicited Local Adverse Events (AEs) Up to 7 Days After Booster Vaccination (Open-label Booster Vaccination Phase);Number of Participants With Solicited Systemic AEs Up to 7 Days After Booster Vaccination (Open-label Booster Vaccination Phase);Number of Participants With Unsolicited AEs Up to 28 Days After Booster Vaccination (Open-label Booster Vaccination Phase)

Number of Participants with Adverse Events of Special Interest (AESI) from Booster Vaccination Until End of the Study (Open-label Booster Vaccination Phase);Number of Participants with First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) with Seronegative Status (Main Study);Number of Participants with First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) with Seronegative Status (Main Study);Number of Participants with First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) with Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants with First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) with Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants with First Occurrence of Molecularly Confirmed Severe/Critical Coronavirus Disease (COVID-19) with Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants with First Occurrence of Molecularly Confirmed Severe/Critical Coronavirus Disease (COVID-19) with Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants with Serious Adverse Events (SAEs) from Booster Vaccination Until End of the Study (Open-label Booster Vaccination Phase);Number of Participants with Solicited Local Adverse Events (AEs) Up to 7 Days After Booster Vaccination (Open-label Booster Vaccination Phase);Number of Participants with Solicited Systemic AEs Up to 7 Days After Booster Vaccination (Open-label Booster Vaccination Phase);Number of Participants with Unsolicited AEs Up to 28 Days After Booster Vaccination (Open-label Booster Vaccination Phase)

Number of Participants with Adverse Events of Special Interest (AESI) from Booster Vaccination Until End of the Study (Open-label Booster Vaccination Phase);Number of Participants with First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) with Seronegative Status (Main Study);Number of Participants with First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) with Seronegative Status (Main Study);Number of Participants with First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) with Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants with First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) with Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants with First Occurrence of Molecularly Confirmed Severe/Critical Coronavirus Disease (COVID-19) with Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants with First Occurrence of Molecularly Confirmed Severe/Critical Coronavirus Disease (COVID-19) with Seronegative Status (Open-label Booster Vaccination Phase);Number of Participants with Serious Adverse Events (SAEs) from Booster Vaccination Until End of the Study (Open-label Booster Vaccination Phase);Number of Participants with Solicited Local Adverse Events (AEs) Up to 7 Days After Booster Vaccination (Open-label Booster Vaccination Phase);Number of Participants with Solicited Systemic AEs Up to 7 Days After Booster Vaccination (Open-label Booster Vaccination Phase);Number of Participants with Unsolicited AEs Up to 28 Days After Booster Vaccination (Open-label Booster Vaccination Phase)

Number of Participants with First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) with Seronegative Status;Number of Participants with First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) with Seronegative Status

Number of Participants with First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) with Seronegative Status;Number of Participants with First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) with Seronegative Status

Number of Participants with First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) with Seronegative Status

Number of Participants with First Occurrence of Molecularly Confirmed Moderate to Severe/Critical Coronavirus Disease (COVID-19) with Seronegative Status