Applicable for both phases of study: 1. Male and female subjects aged between 18 to 70 years (Phase I) / 18 to 75 years (Phase II) (both inclusive) at randomization. 2. Healthy as judged by medical history, physical and other examination or investigations and in the clinical opinion of the Investigator. 3. Subject should be capable and willing to give voluntary written informed consent prior to inclusion in the study. 4. Able to comprehend and comply with study requirements and procedures and be able and willing to complete subject diary. 5. Negative / Non-reactive for antibodies against SARS-CoV-2. 6. Negative / Non-reactive RT-PCR screening of nasopharyngeal swabs/suitable sample for SARS CoV-2 within 72 hours prior vaccination. 7. Male subjects who are sexually active or married and female subjects who are sexually active or married and are of child bearing potential should be willing to follow effective birth control methods for duration of the study. Note: Birth control methods include vasectomised subject/partner, or any 2 of the following methods: intrauterine device, oral, transdermal, injected, or implanted contraceptive, condoms, occlusive cap (diaphragm or cervical vault caps), spermicidal foam/gel/cream, etc. OR Exception to the above are male subjects who are infertile (post vasectomy with documented azoospermia or bilateral orchidectomy) and female subjects who are of non-childbearing potential [who are surgically sterile (hysterectomy, bilateral tubal ligation or bilateral salpingo-oophorectomy) or postmenopausal subjects with amenorrhea for at least 2 years]

Applicable for both phases of study: 1. Male and female subjects aged between 18 to 70 years (Phase I) / 18 to 75 years (Phase II) (both inclusive) at randomization. 2. Healthy as judged by medical history, physical and other examination or investigations and in the clinical opinion of the Investigator. 3. Subject should be capable and willing to give voluntary written informed consent prior to inclusion in the study. 4. Able to comprehend and comply with study requirements and procedures and be able and willing to complete subject diary. 5. Negative / Non-reactive for antibodies against SARS-CoV-2. 6. Negative / Non-reactive RT-PCR screening of nasopharyngeal swabs/suitable sample for SARS CoV-2 within 72 hours prior vaccination. 7. Male subjects who are sexually active or married and female subjects who are sexually active or married and are of child bearing potential should be willing to follow effective birth control methods for duration of the study. Note: Birth control methods include vasectomised subject/partner, or any 2 of the following methods: intrauterine device, oral, transdermal, injected, or implanted contraceptive, condoms, occlusive cap (diaphragm or cervical vault caps), spermicidal foam/gel/cream, etc. OR Exception to the above are male subjects who are infertile (post vasectomy with documented azoospermia or bilateral orchidectomy) and female subjects who are of non-childbearing potential [who are surgically sterile (hysterectomy, bilateral tubal ligation or bilateral salpingo-oophorectomy) or postmenopausal subjects with amenorrhea for at least 2 years]

Applicable for both phases of study: 1. Male and female subjects aged between 18 to 70 years (Phase I) / 18 to 75 years (Phase II) (both inclusive) at randomization. 2. Healthy as judged by medical history, physical and other examination or investigations and in the clinical opinion of the Investigator. 3. Subject should be capable and willing to give voluntary written informed consent prior to inclusion in the study. 4. Able to comprehend and comply with study requirements and procedures and be able and willing to complete subject diary. 5. Negative / Non-reactive for antibodies against SARS-CoV-2. 6. Negative / Non-reactive RT-PCR screening of nasopharyngeal swabs/suitable sample for SARS CoV-2 within 72 hours prior vaccination. 7. Male subjects who are sexually active or married and female subjects who are sexually active or married and are of child bearing potential should be willing to follow effective birth control methods for duration of the study. Note: Birth control methods include vasectomised subject/partner, or any 2 of the following methods: intrauterine device, oral, transdermal, injected, or implanted contraceptive, condoms, occlusive cap (diaphragm or cervical vault caps), spermicidal foam/gel/cream, etc. OR Exception to the above are male subjects who are infertile (post vasectomy with documented azoospermia or bilateral orchidectomy) and female subjects who are of non-childbearing potential [who are surgically sterile (hysterectomy, bilateral tubal ligation or bilateral salpingo-oophorectomy) or postmenopausal subjects with amenorrhea for at least 2 years]

Applicable for both phases of study: 1. Male and female subjects aged between 18 to 70 years (Phase I) / 18 to 75 years (Phase II) (both inclusive) at randomization. 2. Healthy as judged by medical history, physical and other examination or investigations and in the clinical opinion of the Investigator. 3. Subject should be capable and willing to give voluntary written informed consent prior to inclusion in the study. 4. Able to comprehend and comply with study requirements and procedures and be able and willing to complete subject diary. 5. Negative / Non-reactive for antibodies against SARS-CoV-2. 6. Negative / Non-reactive RT-PCR screening of nasopharyngeal swabs/suitable sample for SARS CoV-2 within 72 hours prior vaccination. 7. Male subjects who are sexually active or married and female subjects who are sexually active or married and are of child bearing potential should be willing to follow effective birth control methods for duration of the study. Note: Birth control methods include vasectomised subject/partner, or any 2 of the following methods: intrauterine device, oral, transdermal, injected, or implanted contraceptive, condoms, occlusive cap (diaphragm or cervical vault caps), spermicidal foam/gel/cream, etc. OR Exception to the above are male subjects who are infertile (post vasectomy with documented azoospermia or bilateral orchidectomy) and female subjects who are of non-childbearing potential [who are surgically sterile (hysterectomy, bilateral tubal ligation or bilateral salpingo-oophorectomy) or postmenopausal subjects with amenorrhea for at least 2 years]