Can an influenza vaccine prolong insulin production in children with newly diagnosed diabetes?
This is the hypothesis being investigated by researchers from Steno Diabetes Center at Aarhus University Hospital in the INVITED study, which has previously been nominated for Denmark’s Best Clinical Trial Award. We follow up with this interview with PhD student Ida Borreby Pedersen, who is leading the study.
Ownership and engagement
Ida has a background in medicine, and when one of her supervisors encouraged her to apply for a PhD position at Steno Diabetes Center Aarhus, she did not hesitate to seize the opportunity to work in clinical research. It is a decision she has certainly not regretted.
“I actually came into it through a bit of a side door because I was not the one who came up with the project idea. But I quickly developed a sense of ownership and became very happy to be part of it. I think that is often the case with clinical research – it gets under your skin very quickly,” says Ida.
A hypothesis with major potential
The INVITED study is a placebo-controlled, double-blind trial involving children and young people newly diagnosed with type 1 diabetes. Participants are randomly assigned to receive either a standard influenza vaccine or a placebo vaccine.
The purpose of the study is to investigate whether a standard influenza vaccine can help preserve β-cell function and thereby maintain insulin production for a longer period.
“In this study, we are investigating whether a completely ordinary influenza vaccine can help preserve insulin production in children and young people who have recently been diagnosed with diabetes.”
“In this study, we are investigating whether a completely ordinary influenza vaccine can help preserve insulin production in children and young people who have recently been diagnosed with diabetes. The hypothesis is based on a large study conducted by cardiologist Ole Frøbert, which demonstrated that influenza vaccination improves survival in patients with acute myocardial infarction. Since we know that the cytokines upregulated after acute myocardial infarction are the same as those found in people with type 1 diabetes, it is a natural next step to investigate whether influenza vaccination could also benefit this patient group.”
The hypothesis is that introducing a foreign vaccine modulates immune cells, and that this immune modulation may have a protective effect, rather than the benefit arising from prevention of viral infection itself.
Other researchers have attempted to map the secondary effects of vaccination, but further research is needed.
The influenza vaccine is particularly suitable for this type of study because it is ethically acceptable to conduct a placebo-controlled trial within this patient population.
Fewer newly diagnosed patients have delayed the trial
The goal is to recruit 100 participants, but because fewer children and young people were diagnosed with type 1 diabetes during the first year of the study, recruitment has taken longer than expected.
As a result, the project has expanded to include additional study sites across Denmark.
Although interest and support for the study have been strong, the hypothesis itself has indirectly created challenges in recruiting participants, Ida explains.
“We have actually experienced some parents declining participation because they believe so strongly in the hypothesis.”
“We have actually experienced some parents declining participation because they believe so strongly in the hypothesis. They choose to pay for an influenza vaccination themselves because they do not want to risk their child receiving a placebo vaccine.”
However, while it may be tempting for parents to simply arrange vaccination independently, Ida believes it is important to support the clinical study.
“Although the influenza vaccine is an approved and generally safe treatment, it has not been studied during the acute phase following the onset of type 1 diabetes. When it is administered outside a controlled trial, we lose the opportunity to systematically monitor both its effect and any potential risks. That is precisely why a randomised study is important, even when the treatment is expected to be safe,” Ida emphasises.
The study has currently recruited 77 participants and hopes to enrol the remaining participants before the summer of 2026.
To participate, no more than 14 days may have passed since diagnosis. The vaccine is administered at the start of the study, and participants return for follow-up visits after six and 12 months.
Ida is responsible for analysing the data in collaboration with her supervisory team, which includes paediatricians, cardiologists and clinical pharmacologists. She considers this interdisciplinary approach a major strength.
“It is exciting to look beyond your own speciality, work across disciplines and draw inspiration from what is happening in other fields.”
“It is exciting to look beyond your own speciality, work across disciplines and draw inspiration from what is happening in other fields.”
Funded by an American foundation
The study is funded by the American foundation Flu Lab, which was established by a private investor in 2018 and supports a broad range of research related to influenza and influenza vaccines.
Time is a crucial factor in clinical research
Before Ida had even completed the first year of her PhD programme, she had already applied for and received approval to extend it by an additional year. This gives her four years in total to complete the project. She believes more researchers should have access to this opportunity.
“If we want to support clinical research projects, more PhD students should be allowed to extend their programmes. The process takes a long time: applications, approvals, recruitment, follow-up and evaluation. Naturally, you want to be involved in completing the project you started yourself.”
Ida also notes that the research field itself often determines the opportunities available for pursuing a PhD.
“I have colleagues who had to abandon their dream of doing a PhD because they could not secure funding. Aarhus University offers fully funded PhD positions, but they are difficult to obtain. The research field plays a major role in how easy or difficult it is to secure funding. I have been fortunate to receive funding for both my PhD and my research stay in Australia through grants from the Danish Diabetes Association and the A.P. Møller Foundation.”
Fees create barriers
In January 2024, fees for investigator-initiated, non-commercial clinical trials were reintroduced in Denmark.
Although such studies remain partially exempt from fees charged by the Danish Medicines Agency, Ida believes they still represent a burden and a barrier to clinical research.
“If Denmark genuinely wants to do more to support non-commercial research, these fees should be removed.”
“The application fees charged by the Research Ethics Committee and the annual fees charged by the Danish Medicines Agency are challenging when you are an independent researcher conducting clinical research. If Denmark wants to strengthen support for non-commercial research, removing these fees would be an important step.”
Another challenge Ida has encountered while conducting a study across multiple regions is that, despite Denmark’s small size, different Good Clinical Practice (GCP) units operate according to different procedures.
“When studies are conducted across several regions, researchers have to collaborate with different GCP units that work in different ways. I would like to see greater consistency between the regions – ideally a more harmonised framework that still allows individual hospitals to organise their workflows differently where appropriate.”