In short
Influenza, purified antigen is an inactivated influenza vaccine component used in clinical research. In the EU Clinical Trials Information System, the specific strain INFLUENZA A VIRUS, SUBTYPE H3N2, STRAIN A/MICHIGAN/105/2025 SAN-049A, INACTIVATED appears within authorised trials investigating whether influenza vaccination can preserve beta cell function in early type 1 diabetes and comparing high-dose versus standard-dose influenza vaccines in adults with hematological cancer.
Key points
- Phase 2 and Phase 3 trials are authorised in the EU Clinical Trials Information System.
- One trial studies whether influenza vaccination preserves beta cell function in early type 1 diabetes.
- A second trial compares high-dose versus standard-dose inactivated influenza vaccine in hematological cancer patients.
- The two trials plan to enrol 100 and 180 participants respectively.
- The hematological cancer trial measures seroconversion to at least one of four vaccine antigens at 28 days.
What is influenza, purified antigen?
INFLUENZA A VIRUS, SUBTYPE H3N2, STRAIN A/MICHIGAN/105/2025 SAN-049A, INACTIVATED is an inactivated influenza virus antigen. It is one component of influenza vaccines, which contain split or fragmented inactivated virus particles. The substance appears in the EU Clinical Trials Information System as part of authorised trivalent and quadrivalent influenza vaccines used in clinical research.
How does influenza, purified antigen work?
Inactivated influenza vaccines work by exposing the immune system to fragments of the influenza virus. This exposure trains the immune system to recognise and respond to the virus without causing infection. In the trials listed, the vaccine is being studied for effects beyond routine protection against influenza, including whether vaccination can influence immune responses in type 1 diabetes and hematological cancer.
Which conditions is it used or studied for?
- Type 1 diabetes — a condition where the immune system attacks insulin-producing beta cells in the pancreas. A Phase 2 trial is studying whether influenza vaccination can preserve beta cell function in early type 1 diabetes.
- Hematological cancer — cancers affecting the blood, bone marrow or lymph nodes. A Phase 3 trial compares high-dose and standard-dose influenza vaccines in adults treated for these cancers.
How is influenza, purified antigen given?
The influenza vaccines containing this antigen are given by intramuscular injection. In the trials, the vaccines are administered as suspensions for injection in pre-filled syringes, with a volume of 0.5 ml or 1 ml depending on the product.
What do the clinical trials show?
Two authorised trials in the EU Clinical Trials Information System involve influenza vaccines containing this antigen. The INVITED trial is a Phase 2 study in 100 participants with early type 1 diabetes. Its primary outcome is the change in fasting residual beta cell (C-peptide) function from baseline to 12 months. The Flu-Hemato-Rando study is a Phase 3 single-blind randomised trial in 180 adults treated for hematological cancer. It compares high-dose quadrivalent inactivated influenza vaccine (QIIV-HD) with standard-dose quadrivalent inactivated influenza vaccine (QIIV-SD). The primary endpoint is seroconversion to at least one of the four vaccine antigens at 28 days after vaccination, and a second co-primary endpoint aims to define a baseline signature predicting response to the vaccine.
What side effects are known?
The registry data provided do not include side effect information for this specific antigen. No supplementary sources on side effects were available for this page.