safety and immunogenicity of a booster vaccination with an adapted vaccine

Conditions: SARS-CoV2 Infection

Summary: this is a phase iib/iii, double-blind, randomised, active-controlled, multi-centre, non-inferiority clinical trial that aims to determine safety, tolerability and immunogenicity of a booster vaccination with a recombinant protein receptor binding domain (rbd) fusion homodimer of xbb.1.16 adapted candidate against sars-cov-2 developed by hipra (phh-1v81).

this is a phase iib/iii, double-blind, randomised, active-controlled, multi-centre, non-inferiority clinical trial that aims to determine safety, tolerability and immunogenicity of a booster vaccination with a recombinant protein receptor binding domain (rbd) fusion homodimer of xbb.1.16 adapted candidate against sars-cov-2 developed by hipra (phh-1v81). approximately 612 participants who have received a primary scheme with an eu-approved mrna vaccine (two doses) and at least one booster dose of an eu-approved mrna vaccine against covid-19, will be randomly assigned to the following two treatment arms in a phh-1v81 : comirnaty (omicron xbb.1.5) 2:1 ratio: * phh-1v81 vaccine arm: approximately 408 adults will receive a booster dose of phh-1v81 (hipra adapted vaccine). * comirnaty vaccine arm: approximately 204 adults will receive a booster dose of comirnaty omicron xbb.1.5. participants will be stratified before randomisation by age group (approximately 10% of adults ≥60 years old), and by number of doses previously received. all participants will receive a booster dose of phh-1v81 or comirnaty omicron xbb.1.5 at day 0 and will be followed for 6 months. all subjects will be closely observed for 15 minutes after vaccination on site.

Eligibility criteria:
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.