A report from the BBC....
Scientists fear that a vaccine for a virus that kills thousands of children worldwide every year may lead to childhood diabetes.
But there is still a chance that the vaccine could actually protect against diabetes as well as the virus.
Rotavirus infection can lead to a diarrhoeal illness which is extremely dangerous in the young, weak and otherwise vulnerable.
Teams around the world are working on a vaccine for the virus, with some degree of success.
However, Dr Margo Honeyman, from the Walter and Eliza Hall Institute of Medical Research in Melbourne, Australia, says there is a possible link between rotavirus infection and type I diabetes, which can leave a patient reliant on insulin injections for life.
Type I diabetes involves an unwanted immune system response which targets cells in the pancreas which produce insulin, a hormone vital to the control of blood sugar levels.
Dr Honeyman had noticed that parts of some rotavirus proteins were similar to parts of proteins on the pancreatic cells which have been linked to the destructive immune response.
All babies infected
She looked at 54 babies who each had a relative with type I diabetes, and so were thought to be vulnerable to the condition.
All the children became infected with some form of rotavirus during the study.
In the 24 babies who appeared to be developing type I diabetes, levels of antibodies in their blood that signal an attack on the pancreas went up every time they got a rotavirus infection.
This effect was not present in children who didn't go on to develop diabetes.
Although the evidence is that rotavirus infection are linked to the destructive immune attack on the pancreas, it is not clear exactly how.
One theory is that the virus mimics body chemicals which "incite" the body to attack its own pancreatic cells.
If this proves to be the case, then some rotavirus vaccines which include versions of the virus itself could be thrown into doubt.
Dr Honeyman said: "If rotavirus is directly infecting the pancreas then a vaccine will be safe and protective.
"But if it is mimicry alone, or both infection and mimicry, the vaccines may be dangerous."
Dr David Cubitt, a virologist from Great Ormond Street Hospital in London, said: "It's fairly convincing evidence that rotavirus might be one of the triggers for juvenile onset diabetes."