Safety and Immunogenicity of a Booster Vaccination With an Adapted Vaccine

Inclusion Criteria: * Adults aged 18 or older at Day 0 * Are willing and able to sign the informed consent and can comply with all study visits and procedures * Participant must have received a primary scheme of an EU-approved mRNA vaccine (2 doses) and at least one booster dose with an EU-approved mRNA vaccine. Last booster dose must have been administered at least 6 months before Day 0. * Having a negative Rapid Antigen Test for COVID-19 at Day 0 prior to vaccination. * Adults determined by clinical assessment, including medical history and clinical judgement, to be eligible for the study, including adults with pre-existing chronic and stable diseases (non-immunocompromised), if these are stable and well-controlled according to the investigator's judgment. * Uses an accepted method of contraception Exclusion Criteria: * Participant with an acute illness with fever ≥ 38.0°C at Day 0 or within 24 hours prior to vaccination. Afebrile participants with minor illnesses can be enrolled at the discretion of the investigator * Participant with a medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behaviour that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study. * Participant with history of severe adverse reaction associated with a vaccine and/or severe allergic reaction (e.g. anaphylaxis) to any component of the study intervention * Immunocompromised individuals defined as those with primary and secondary immune deficiencies and those receiving chemotherapy or immunosuppressant drugs other than steroids and glucocorticoids (maximum 30mg/day of prednisone, or equivalent, by any administration route for a maximum of 30 consecutive days), within 90 days prior to vaccination * Participant with a bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection * Have receipt of blood-derived immune globulins, blood, or blood-derived products in the past 3 months * Participation in other studies involving study intervention if last dose is within 28 days prior to screening and/or it is planned to receive during study participation * Received any non-study vaccine within 14 days before or after screening. For live or attenuated vaccines, 4 weeks before or after screening * Received any COVID-19 vaccines other than EU-approved mRNA vaccines * Received any Omicron XBB adapted vaccine before Day 0 * COVID-19 infection diagnosed in the previous 6 months before Day 0. History of COVID-19 infections is allowed * History of a diagnosis or other conditions that, in the judgment of the investigator, may affect study endpoint assessment or compromise participant safety.