Dose Finding Study to Evaluate The Safety, Tolerability and Immunogenicity of an Inactiviated, Adjuvanted SARS-CoV-2 Virus Vaccine Candidate Against Covid-19 in Healthy Subjects

Inclusion Criteria - Subjects who meet ALL of the following criteria are eligible for the study:

• Participant is 18 to 55 years of age
• Participant who has a smart phone and is willing and able to install and use the eDiary.
• Participant has an understanding of the study and its procedures, agrees to its provisions, and voluntarily gives written informed consent prior to any study-related procedures.
• Participant is generally healthy as determined by the Investigator
• Participant has a Body Mass Index (BMI) of 18.0-30.0 kg/m2
• If subject is of childbearing potential:
• Participant has practiced an adequate method of contraception during the 30 days before screening (Visit 0).
• Participant has a negative serum or urine pregnancy test at screening (Visit 0) or Visit 1, respectively.
• Participant agrees to employ adequate birth control measures up to Day 106 (Visit 5).

Inclusion Criteria for Booster Phase - Subjects who meet ALL of the following criteria are eligible for the Booster phase:

• B1. Participant has received complete VLA2001 primary immunization (two vaccinations according to the protocol)
• B2. Participant who has a smart phone and is willing and able to install and use the e-Diary.
• B3. Participant has an understanding of the study and its procedures, agrees to its provisions, and voluntarily gives written informed consent prior to any study-related procedures.
• B4. Participant is generally healthy as determined by the Investigator's clinical judgement
• B5. If a participant is of childbearing potential:
• Participant has a negative urine pregnancy test at Visit 7 prior to booster vaccination.
• Participant agrees to employ adequate birth control measures up to 3 months after the Booster vaccination.

Exclusion criteria - Participants who meet ANY of the following criteria are NOT eligible for this study:

• Clinically significant infection or other acute illness, including fever ≥ 38°C within 24 hours prior to the planned study vaccination.
• History of laboratory-confirmed SARS-CoV-2 infection.
• Participant had close contact to persons with confirmed SARS-CoV-2 infection within 30 days prior to screening (Visit 0).
• Participant has participated in a clinical study involving an investigational SARS-CoV-2 vaccine.
• Participant has an acute or recent infection not due to SARS-CoV-2
• Participant has a history of SARS-CoV-1 or MERS infection (self-reported)
• Participant tests positive for human immunodeficiency virus (HIV), hepatitis B surface antigen (HBsAg) or hepatitis C virus (HCV).
• Participant has received any vaccine within 30 days prior Visit 1 other than the study intervention, with the exception of the seasonal influenza vaccination.
• Participant has abnormal findings in any required study investigations (including medical history, physical examination, and clinical laboratory) considered clinically relevant by the Investigator.
• Participants with either medical history of or present acute or progressive, unstable or uncontrolled clinical conditions that pose a risk for participation or completion of the study, based on Investigator's clinical judgement.
• Participants with underlying diseases with a high risk of developing severe COVID-19 symptoms if infected
• Participant has a history of malignancy in the past 5 years other than squamous cell or basal cell skin cancer. If there has been surgical excision or treatment more than 5 years ago that is considered to have achieved a cure, the subject may be enrolled. A history of hematologic malignancy is a permanent exclusion. Participants with a history of skin cancer must not be vaccinated at the previous tumour site.
• Participant has a known or suspected defect of the immune system, such as Participants with congenital or acquired immune deficiency
• Participant received immuno-suppressive therapy within 4 weeks prior to Visit 1 or receipt of immunosuppressive therapy is expected during the study.
• Part