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 …