Table of contents
- Trial overview
- Who participated
- What was studied
- Study goals and endpoints
- How results were measured
- Trial status and size
Trial overview
The main study in the source data was The Celljuvant study, a Phase 3 interventional trial in adults aged 50 years and older.[1] It investigated an adjuvanted quadrivalent subunit inactivated cell-derived influenza vaccine and included A/(H3N2)-LIKE VIRUS ANTIGEN as one of the influenza strain components studied in the vaccine program.[1]
This trial was designed to look at both immunogenicity and safety-related study data in a large older adult population.[1] The study was completed and enrolled 6300 participants.[1]
Who participated
The target population included healthy individuals and people with stable comorbidities, meaning other health conditions that were present but not changing quickly.[1] These stable conditions were important because they increased the risk of complications from influenza infection.[1]
The age group was adults 50 years and older.[1] This makes the study relevant to older adults, who often have a higher risk of serious flu illness.[1]
What was studied
The trial compared 3 consecutive vaccine lots of aQIVc HD to check whether they gave similar immune responses.[1] This is called lot-to-lot consistency, which means checking that different batches of the same vaccine behave in a similar way.[1]
The study also compared aQIVc HD with QIVr and aQIV to see whether the immune response was not worse than the comparison vaccines.[1] This type of comparison is called noninferiority, which means the new vaccine is tested to see whether it performs at least as well as the comparator within a planned margin.[1]
The influenza strain information in the source data included A/DARWIN/9/2021 (H3N2)-LIKE STRAIN and other influenza strains used in the vaccine program.[1] The study focused on immune responses against the four vaccine strains using cell-derived target viruses.[1]
Study goals and endpoints
The first main goal was to show clinical lot-to-lot consistency across 3 consecutive lots of aQIVc HD.[1] The trial measured this by looking at the Day 29 ratio of geometric mean titers for antibodies against each vaccine strain.[1]
The second main goal was to show immunological noninferiority of aQIVc HD versus QIVr and versus aQIV for each vaccine strain.[1] The main immune endpoints were Day 29 GMT, Day 29 GMTr, and seroconversion rate from Day 1 to Day 29, plus the difference in seroconversion rates between study groups.[1]
These endpoints are blood-based measurements that help researchers understand how well the body responds after vaccination.[1] They do not measure whether a person gets flu symptoms directly; they measure the immune reaction instead.[1]
How results were measured
The study used a hemagglutination inhibition (HI) assay, a blood test that measures antibodies against influenza viruses.[1] In simple terms, this test helps show whether the immune system has made antibodies that can recognize the flu strains in the vaccine.[1]
The main time point named in the trial data was Day 29.[1] The study also measured the change from Day 1 to Day 29 for seroconversion rate, which shows how many participants developed a stronger antibody response after vaccination.[1]
Trial status and size
The study was listed as Completed.[1] It enrolled 6300 participants, making it a large Phase 3 trial.[1]
Because the source data focused on immune response endpoints, the main value of this trial is in understanding how well different vaccine lots and comparator vaccines performed in older adults.[1] The data support research on influenza vaccination in a population at higher risk for complications.[1]
