inclusion criteria: all the following criteria need to be met for inclusion: 1. adults in good health as determined by the principal investigator or sub-investigator between 18 - 55 years old inclusively. 2. able to provide informed consent and willing to comply with the study procedures. 3. bmi ≥ 18.0 kg/m2 and ≤ 35.0 kg/m2, with weight ≥ 45 kg for female subjects and ≥ 50 kg for male subjects. 4. vital signs within the following limits: systolic blood pressure (bp) 90 - 140 mmhg, inclusive; diastolic bp 40 - 90 mmhg, inclusive; heart rate 40 - 100 bpm, inclusive; respiratory rate 10 - 22 bpm, inclusive; temperature 35.5 - 37.5 °c, inclusive. 5. women of child-bearing potential should have a negative serum pregnancy test at screening and a confirmatory negative urine pregnancy test at baseline (day 0, defined as enrolment), one before the second administration (day 14) and one before the third and last dose administration (day 28). 6. agrees to practice acceptable contraception during the study if female of child-bearing potential or male partner of female of child-bearing potential. 7. physical examination, clinical assessments, and laboratory values within normal limits during screening, unless assessed as not clinically significant by investigator or delegate. 8. has received a dose or multiple doses, of a registered covid-19 vaccine, with the last dose more than two months prior to enrolment.

inclusion criteria: all the following criteria need to be met for inclusion: 1. adults in good health as determined by the principal investigator or sub-investigator between 18 - 55 years old inclusively. 2. able to provide informed consent and willing to comply with the study procedures. 3. bmi ≥ 18.0 kg/m2 and ≤ 35.0 kg/m2, with weight ≥ 45 kg for female subjects and ≥ 50 kg for male subjects. 4. vital signs within the following limits: systolic blood pressure (bp) 90 - 140 mmhg, inclusive; diastolic bp 40 - 90 mmhg, inclusive; heart rate 40 - 100 bpm, inclusive; respiratory rate 10 - 22 bpm, inclusive; temperature 35.5 - 37.5 °c, inclusive. 5. women of child-bearing potential should have a negative serum pregnancy test at screening and a confirmatory negative urine pregnancy test at baseline (day 0, defined as enrolment), one before the second administration (day 14) and one before the third and last dose administration (day 28). 6. agrees to practice acceptable contraception during the study if female of child-bearing potential or male partner of female of child-bearing potential. 7. physical examination, clinical assessments, and laboratory values within normal limits during screening, unless assessed as not clinically significant by investigator or delegate. 8. has received a dose or multiple doses, of a registered covid-19 vaccine, with the last dose more than two months prior to enrolment.

inclusion criteria: all the following criteria need to be met for inclusion: adults in good health as determined by the principal investigator or sub-investigator between 18 - 55 years old inclusively. able to provide informed consent and willing to comply with the study procedures. bmi ≥ 18.0 kg/m2 and ≤ 35.0 kg/m2, with weight ≥ 45 kg for female subjects and ≥ 50 kg for male subjects. vital signs within the following limits: systolic blood pressure (bp) 90 - 140 mmhg, inclusive; diastolic bp 40 - 90 mmhg, inclusive; heart rate 40 - 100 bpm, inclusive; respiratory rate 10 - 22 bpm, inclusive; temperature 35.5 - 37.5 °c, inclusive. women of child-bearing potential should have a negative serum pregnancy test at screening and a confirmatory negative urine pregnancy test at baseline (day 0, defined as enrolment), one before the second administration (day 14) and one before the third and last dose administration (day 28). agrees to practice acceptable contraception during the study if female of child-bearing potential or male partner of female of child-bearing potential. physical examination, clinical assessments, and laboratory values within normal limits during screening, unless assessed as not clinically significant by investigator or delegate. has received a dose or multiple doses, of a registered covid-19 vaccine, with the last dose more than two months prior to enrolment.

inclusion criteria: all the following criteria need to be met for inclusion: adults in good health as determined by the principal investigator or sub-investigator between 18 - 55 years old inclusively. able to provide informed consent and willing to comply with the study procedures. bmi ≥ 18.0 kg/m2 and ≤ 35.0 kg/m2, with weight ≥ 45 kg for female subjects and ≥ 50 kg for male subjects. vital signs within the following limits: systolic blood pressure (bp) 90 - 140 mmhg, inclusive; diastolic bp 40 - 90 mmhg, inclusive; heart rate 40 - 100 bpm, inclusive; respiratory rate 10 - 22 bpm, inclusive; temperature 35.5 - 37.5 °c, inclusive. women of child-bearing potential should have a negative serum pregnancy test at screening and a confirmatory negative urine pregnancy test at baseline (day 0, defined as enrolment), one before the second administration (day 14) and one before the third and last dose administration (day 28). agrees to practice acceptable contraception during the study if female of child-bearing potential or male partner of female of child-bearing potential. physical examination, clinical assessments, and laboratory values within normal limits during screening, unless assessed as not clinically significant by investigator or delegate. has received a dose or multiple doses, of a registered covid-19 vaccine, with the last dose more than two months prior to enrolment.