COV-COMPARE Immunogenicity of Vaccine VLA2001 Compared to AZD1222

Approximately 4000 Adult participants will be recruited in the study. About 3000 participants aged 30 years and above will be randomized in a 2:1 ratio to receive 2 intramuscular recommended doses of either VLA2001 (n=2000) or AZD1222 (n=1000). In addition, approximately 1000 subjects aged 18-29 years will participate in this study in a non-randomized, open-label fashion to receive VLA2001. The 2 doses of vaccination for both vaccines will be administered 28 days apart, on Days 1 and 29. All visits will be conducted at the clinical site on an outpatient basis. All participants - except those who already received a licensed COVID-19 vaccine outside of the study - will be offered a booster dose with VLA2001 between Jan and Mar 2022 and will have a follow-up visit 14 days (Visit B2) and 6months after the booster dose. Approximately 660 Adolescent participants were planned to be recruited and randomized in a 1:1 ratio to receive 2 intramuscular doses of either VLA2001 (n=330) or placebo (n=300). Participants in the placebo group will receive a 2-dose primary immunization with VLA2001 on Day 85 and the second vaccination 28 days later. For safety reasons, the first 16 adolescents will be enrolled in an open label, non-randomized manner (sentinel dosing). Recruitment of adolescent participants has been stopped after recruitment of 6 randomized participants (3 randomized to VLA2001 and 3 participants randomized to placebo) due to the low recruitment rate. The study design ensures a safety follow-up of at least 6 months after the last VLA2001 vaccination/booster for all enrolled study participants Participants will be provided with an electronic Diary (e-Diary) and will be trained to record specifically solicited systemic and local symptoms daily as well as any additional AEs during follow-up period after each of both vaccinations up to the next visit to the site until Day 43 visit has been completed.