October 1, 2026

expert reaction to study examining incidence of type 1 diabetes in children receiving rotavirus vaccine; secondary analysis suggests vaccine not cause of observed 11% relative increase

Scientists comment on a study examining incidence of type 1 diabetes in children receiving rotavirus vaccine; secondary analysis suggests vaccine not cause of observed 11% relative increase, as published in Diabetologia.

Prof Saul Faust, Professor of Paediatric Immunology and Infectious Diseases, University of Southampton, said:

“This is an interesting paper that investigated the causal link between rotavirus vaccines and the onset of diabetes. Despite the “headline” outcome, the researchers are clear in their interpretation and secondary analysis that their data do not necessarily suggest a causal link between rota vaccine and the observation of a slight increase in diabetes onset. Further investigation and method development is needed to be able to tease out real associations between vaccines and possible effects on this and many other childhood and paediatric conditions.”

Prof Adam Finn, Emeritus Professor of Paediatrics, University of Bristol, said:

“This report describes a negative result. The authors were looking to see whether prevention of rotavirus infection by vaccination was followed by a reduction in the incidence of type 1 diabetes in children. This is a reasonable hypothesis as there is much evidence to suggest that early viral infections in susceptible children can trigger diabetes which is an autoimmune disease of insulin-producing cells of the pancreas. 

“The study did not deliver evidence that introducing the vaccine coincided with a fall in occurrence of new cases of this disease in children. This does not prove that it doesn’t (it’s hard to prove a negative) but it didn’t suggest that it does either. 

“To their surprise they detected more new cases of diabetes after the introduction of the vaccine than expected. 

“There are multiple possible reasons why this may have happened. 

“Accordingly, they then looked hard at their data to try and understand it better. While they couldn’t reach any firm conclusion as to what the reason or reasons for the apparent increase was (it’s hard to do this using a study of this kind in this way), they were able to conclude with reasonable confidence that the rotavirus vaccine programme was not the cause.

“A reasonable metaphor for this report and conclusion would be to point out that while the fall in the birth rate in Germany in the 1990s coincided with a fall in the number of nesting storks in that country, it would be misleading to conclude that this proves that babies arrive carried by storks.”

Prof Alex Richter, Professor and Honorary Consultant in Clinical Immunology, University of Birmingham, said:

“Saying that the rotavirus vaccine is ‘linked to an increased risk of type 1 diabetes’ could give parents the wrong impression. The study found that rates of type 1 diabetes went up after the vaccine programme was introduced, but that does not mean the vaccine caused the increase. When the researchers looked at the data in different ways, including directly comparing vaccinated and unvaccinated children, the apparent increase was no longer statistically significant. So this study questions whether rotavirus vaccination protects against type 1 diabetes, but it does not provide convincing evidence that the vaccine increases the risk.

“This is a large and carefully conducted study, and the researchers have been appropriately cautious about their findings. The difficulty is that lots of things change over time. Seeing type 1 diabetes increase after a vaccine programme starts does not tell us that the vaccine caused that increase. In fact, the researchers saw very similar increases in type 1 diabetes around changes to two completely different vaccination programmes. That is a good illustration of why we need to be very careful about assuming cause and effect from this type of study.”

‘Rotavirus vaccination and incidence of type 1 diabetes: a population‑based natural experiment’ by Maria Östman et al. was published in Diabetologia at 23:01 UK time on Thursday 1st October.

DOI: 10.1007/s00125-026-06832-0

Declared interests

Prof Saul Faust: “I act as chief and principal investigator, and attend advisory boards and symposia, for multiple manufacturer’s commercial vaccine trials on behalf of University Hospital Southampton NHS Foundation Trust. All my work with vaccine companies is contracted by my organisation (UHS NHS FT) with no personal payments.”

Prof Adam Finn: “AF undertakes paid consultancy for multiple vaccine developers and manufacturers including GSK and MSD who make rotavirus vaccines.”

Prof Alex Richter: “I have no CoI for this”