In short
Clinical trials are studying INFLUENZA INACTIVATED SPLIT VIRUS STRAIN A (H1N1) in adults 18 years and older. These studies look at immune response, safety, and reactogenicity, which means how often short-term reactions happen after vaccination. The trials focus on people with human influenza and test vaccine performance in Phase 2 studies.
Key points
- These clinical trials study INFLUENZA INACTIVATED SPLIT VIRUS STRAIN A (H1N1) in adults 18 years and older. Both trials are Phase 2 studies and focus on immune response and safety. The main condition studied is human influenza. Researchers measure antibody response, including titer, seroconversion, and seroprotection, as well as short-term and longer-term safety outcomes. One trial is completed and one is authorised. The studies include 770 participants in one trial and 960 in the other.
Trial overview
Two interventional studies investigated INFLUENZA INACTIVATED SPLIT VIRUS STRAIN A (H1N1) as part of influenza vaccine research in adults. Both studies were designed to assess the immune response and safety of vaccine interventions in people with human influenza.
Who was studied
The target population in both trials was adults 18 years of age and older. The condition listed for both studies was Influenza, Human, which means the trials focused on influenza in people rather than in animals or in a lab-only setting.
These studies did not describe children, pregnant people, or other special groups in the source data, so the trial population described here is limited to adults.
What was measured
The main goal was to evaluate the humoral immune response, which means the antibody response made by the blood after the study intervention. The studies measured antibody titer at Day 29, the fold increase in antibody titer from Day 1 to Day 29, seroconversion from Day 1 to Day 29, and seroprotection at Day 1 and Day 29.
Safety was also a major focus. The trials tracked solicited administration site or systemic events within 7 days, unsolicited adverse events within 28 days, serious adverse events within 6 months, adverse events of special interest within 6 months, medically attended adverse events within 6 months, and laboratory abnormalities at pre-dose and after dosing on Days 3, 8, and 29.
Trial status and size
One study, NCT07204964, was Authorised and planned to enroll 960 participants. The other study, 2025-522278-35-00, was Completed and enrolled 770 participants.
Both studies were relatively large Phase 2 trials, which helps researchers collect more information about immune response and safety before moving to later development steps.
Study design and phase
Both trials were interventional, meaning the researchers gave study vaccines and then observed the results. Each study was in Phase 2, which is a stage used to learn more about how the vaccine performs in a larger group after earlier testing.
The intervention lists included INFLUENZA INACTIVATED SPLIT VIRUS STRAIN A (H1N1) as part of trivalent influenza vaccine comparisons and related vaccine formulations, all given by intramuscular use. The source data also included other influenza vaccine components and recombinant hemagglutinin products, but the trial focus remained the immune response and safety of the study interventions.
Key terms explained
Antibody titer is a blood test measure of how much antibody is present. Seroconversion means a person develops a measurable antibody response after the study intervention. Seroprotection means the antibody level is considered high enough to suggest protection.
Solicited events are symptoms that participants are asked to watch for and report, while unsolicited adverse events are any other unwanted health problems that come up during the study. Serious adverse events are more severe health problems, and laboratory abnormalities are test results outside the normal range.