In short
INFLUENZA A VIRUS, SUBTYPE H1N1, STRAIN A/SWITZERLAND/6849/2025 IVR-278, INACTIVATED is an inactivated influenza virus strain used as a component in influenza vaccines. It appears in two authorised clinical trials: a Phase 2 trial in 100 people with early type 1 diabetes, and a Phase 3 trial in 180 adults with hematological cancer. The substance data identifies it as a placebo component in one of these trial records.
Key points
- Phase 2 trial in type 1 diabetes with 100 participants, authorised but not yet recruiting.
- Phase 3 trial in hematological cancer with 180 participants, authorised but not yet recruiting.
- The type 1 diabetes trial measures change in fasting residual beta cell function over 12 months.
- The cancer trial compares high-dose versus standard-dose inactivated influenza vaccine.
- This H1N1 strain is a component of influenza vaccines, not a standalone medicine.
- Both trials are listed as authorised in the EU Clinical Trials Information System.
What is influenza A H1N1 vaccine strain?
INFLUENZA A VIRUS, SUBTYPE H1N1, STRAIN A/SWITZERLAND/6849/2025 IVR-278, INACTIVATED is an inactivated influenza virus strain. It is a component of influenza vaccines rather than a medicine given on its own. In the trial records, the substance appears as a placebo in one trial, where it is listed as 0.9% sodium chloride for intramuscular injection from hospital stock. The other trial uses trivalent and quadrivalent influenza vaccines that contain inactivated, split virion influenza strains, including H1N1 components.
How does influenza A H1N1 vaccine strain work?
Inactivated influenza virus strains such as this H1N1 strain are used in vaccines to stimulate an immune response against influenza. Because the virus is inactivated, it cannot cause influenza infection. The trial in type 1 diabetes is investigating whether influenza vaccination can help preserve beta cell function in early type 1 diabetes, based on the idea that vaccination may influence the immune system in a way that protects insulin-producing cells. The cancer trial measures seroconversion, which is the development of detectable antibodies against vaccine antigens, as a way to assess how well the immune system responds to vaccination.
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. The Phase 2 trial is studying whether influenza vaccination can preserve remaining beta cell function in people with early type 1 diabetes.
- Hematological cancer — cancers affecting the blood, bone marrow or lymph nodes, such as myeloma, other B-cell malignancies and myeloid malignancies. The Phase 3 trial is comparing high-dose versus standard-dose influenza vaccine in adults being treated for these cancers.
How is influenza A H1N1 vaccine strain given?
The trial records describe the vaccines as suspensions for injection given by intramuscular injection. Doses in the trial records are listed as 0.5 ml or 1 ml, depending on the vaccine product. The placebo in the type 1 diabetes trial is 0.5 ml of 0.9% sodium chloride given by intramuscular injection.
What do the clinical trials show?
Two authorised trials involve this H1N1 strain as part of influenza vaccines. The INVITED trial is a Phase 2 study in 100 people with early type 1 diabetes. It measures 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 with hematological cancer. It compares high-dose quadrivalent inactivated influenza vaccine against standard-dose quadrivalent vaccine, with a co-primary endpoint of seroconversion to at least one of the four vaccine antigens at 28 days after vaccination, and a second co-primary endpoint to define a baseline signature predicting response to the vaccine.
Who can take part in these trials?
The INVITED trial is designed for people with early type 1 diabetes. The Flu-Hemato-Rando study is designed for adults treated for hematological cancer, with recruitment stratified by disease group: approximately 80 myeloma patients, 40 other B-cell malignancy patients and 20 patients treated for a myeloid malignancy. The study also includes 40 healthy control subjects for the systems biology part of the research.
What side effects are known?
No side effect data for this specific H1N1 strain is provided in the trial records or supplementary sources. The trial records do not report adverse event data for this strain.