By Lisa Rapaport

(Reuters Health) – Young kids who receive the rotavirus vaccine may be less likely to develop type 1 diabetes than children who don’t get this routine childhood vaccination, an Australian study suggests.

Rotavirus can cause severe watery diarrhea, vomiting, fever, and abdominal pain. Some children can become extremely dehydrated, requiring hospitalization to prevent fatalities. Rotavirus infections are also thought to accelerate the development of type 1 diabetes, although the exact reason for this connection isn’t clear.

In the current study, researchers compared rates of type 1 diabetes in the eight years before and the eight years after May, 2007, when a routine oral rotavirus vaccine was introduced for infants six weeks and older.

After the vaccine’s debut, type 1 diabetes cases declined 14 percent among children age four and younger, researchers report in JAMA Pediatrics. There wasn’t a meaningful change in type 1 diabetes cases among older kids, however.

“Whilst this finding is only preliminary data, it is possible that rotavirus vaccination may be one of possibly many as yet unknown protective environmental and modifiable factors against the development of type 1 diabetes in early childhood,” lead study author Dr. Kirsten Perrett of the University of Melbourne in Australia.

“At this stage however, we do not know what causes type 1 diabetes,” Perrett said by email. “It has not been clearly linked to other modifiable lifestyle factors and cannot be prevented.”

The most common form of the disease, type 2 diabetes, is linked to obesity and aging and happens when the body can’t properly use or make enough of the hormone insulin to convert blood sugar into energy. The less common form, type 1 diabetes, develops in childhood or young adulthood and occurs when the pancreas produces no insulin at all.

Rotavirus can impair insulin production in the pancreas, which may hasten the development of type 1 diabetes, Perrett said.

An older vaccine to prevent the virus, RotaShield, was introduced and withdrawn in the late 1990s after it was linked to a rare but life-threatening intestinal obstruction known as intussusception.

Two new vaccines, RotaTeq and Rotarix, were introduced about a decade ago and, so far, appear to have a lower risk of intussusception than RotaShield.

After the debut of the new rotavirus vaccine in Australia, the proportion of children four years old and younger diagnosed with type 1 diabetes dropped from 8.7 to 7.5 cases for every 100,000 kids.

The study wasn’t a controlled experiment designed to prove whether or how rotavirus causes type 1 diabetes or how vaccination might help minimize this risk.

Still, the results add to the evidence linking viral infections to autoimmune disorders like type 1 diabetes and celiac disease in otherwise susceptible people, said Dr. Federico Martinon-Torres a researcher at Hospital Clínico Universitario de Santiago and Instituto de Investigacion Sanitaria de Santiago in Spain.

“Rotavirus have been associated with an increased incidence of celiac disease and type 1 diabetes,” Martinon-Torres, who wasn’t involved in the study, said by email. “Inflammatory response against rotavirus in early stages of immune maturation is associated with tolerance breakdown and immune dysregulation.”

Only children with severely compromised immune systems or a history of bowel obstruction should skip the rotavirus vaccine, Martinon-Torres said, essentially meaning nearly every newborn can get be inoculated.

“Rotavirus vaccination of young infants should be recommended to every family with a newborn baby primarily since the vaccination protects effectively against rotavirus infections and the need of hospitalization of the child affected by an acute rotavirus infection,” said Dr. Mikael Knip, a researcher at the University of Helsinki in Finland who wasn’t involved in the study.

“If a protective effect of the vaccine against type 1 diabetes can be confirmed this then provides a bonus,” Knip said by email.

SOURCE: JAMA Pediatrics, online January 22, 2019.