Thanks to its pretty impressive National Immunisation Program, Australia eliminated rubella in 2018 and is now on track to be the first country in the world to eradicate cervical cancer. And according to new research, another routine vaccination appears to have a very desirable, yet unexpected, side effect – it might help prevent the onset of type 1 diabetes.

The vaccine in question protects against rotavirus – an infection that causes severe vomiting and diarrhea in infants – and is administered at age 2-4 months. Writing in JAMA Pediatrics, a team of researchers think the vaccination might have something to do with a recent decline in children being diagnosed with type 1 diabetes – the first time a drop in diagnoses has been seen in Australia since the 1980s.

Type 1 diabetes occurs when immune cells turn on vital insulin-making cells in the pancreas, preventing the body from regulating blood sugar levels. Current treatment involves daily injections of insulin, but scientists are working on finding more desirable solutions.

Studying the prevalence of type 1 diabetes in children between 2000 and 2015, the team discovered that since 2007, the number of children aged 0-4 diagnosed with the disease has declined by 14 percent.

"The significant decrease in type 1 diabetes that we detected in young children after 2007 was not seen in older children aged 5-14. This suggests the young children could have been exposed to a protective factor that didn't impact older children," explained study lead Dr Kirsten Perrett, of Australia's Murdoch Children’s Research Institute, in a statement.

"We observed the decline in the rate of type 1 diabetes in children born after 2007 coincided with the introduction of the oral rotavirus vaccine onto the Australian National Immunisation Program in 2007."

Two decades ago, the same research team discovered a connection between immune markers of type 1 diabetes in children and rotavirus infection. They later found that rotavirus can cause a mouse's immune system to attack insulin-producing cells in the pancreas, which sounds suspiciously similar to how type 1 diabetes develops.

However, the new research does not suggest that rotavirus causes diabetes, simply that there appears to be some kind of connection between the two. The team note that a previous study conducted in Finland found no such link, although the phenomenon might vary between countries due to differing genetic and environmental factors.

“We will be continuing this research to look more closely at the correlation, by comparing the health records of young children with or without type 1 diabetes,” said senior author Professor Len Harrison.

"At this stage we don't yet know whether the reduction in type 1 diabetes is a permanent effect or transient, and it may only be relevant to Australian children."