Rotavirus is the major cause of gastroenteritis (stomach flu) in infants worldwide. Gastroenteritis-linked mortality in infants has substantially decreased since the advent of rotavirus vaccination. However, a surprising effect of the vaccination observed was a 15% decrease in the risk of type 1 diabetes in vaccinated children.
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A complete vaccination against rotavirus in the early months of life has been found to reduce the risk of developing type 1 diabetes later on.
What is stomach flu?
Stomach flu is a type of gastrointestinal tract infection caused by various types of viruses, including rotavirus and norovirus. Although in adults rotavirus infection mostly remains asymptomatic, it can be fatal in infants, younger children, elderly people, and patients with a compromised immune system.
Since there is no particular treatment for stomach flu, getting vaccinated is the best way to prevent the infection. There are two main types of rotavirus vaccines: one is given in three doses at two months, four months, and six months of age, and the other one is given in two doses at two and four months of age. According to the Centers for Disease Control and Prevention, rotavirus vaccination should be completed before infants are eight months old.
According to studies, vaccinating against stomach flu viruses greatly reduces the risk of infants becoming severely ill and needing hospitalization. It has been found that rotavirus vaccination reduces the risk of stomach flu-related and other reason-related hospitalization by 94% and 31%, respectively.
How is stomach flu vaccine-related to type 1 diabetes?
A recent study involving 1,474,535 infants has revealed that compared to unvaccinated infants, rotavirus vaccinated infants have a 33% lower risk of developing type 1 diabetes later in life. Similarly, an Australian study has claimed that there is a 14% reduction in the incidence of type 1 diabetes after the introduction of the rotavirus vaccination program in 2007.
According to some studies, the risk of type 1 diabetes is particularly lower in children vaccinated with all three doses of the pentavalent vaccine as compared to those vaccinated with two doses of the monovalent vaccine. The pentavalent vaccine is more effective as it provides protection against five types of rotavirus. In contrast, the monovalent vaccine is effective against only one type of rotavirus.
The risk of type 1 diabetes in children who have started the vaccination but failed to receive all the doses was the same as that in children who did not receive rotavirus vaccination. In this context, one important thing to remember is some children who have completed the entire rotavirus vaccination process can still develop type 1 diabetes. This indicates that there are other associated factors responsible for the disease pathogenesis.
There are also contradictory studies that did not find any association between rotavirus vaccination and type 1 diabetes risk in childhood and adolescence. Conducted between 2001 and 2003, the Rotavirus Efficacy and Safety Trial studied participant children vaccinated with RotaTeq vaccine or placebo. Results of a questionnaire sent to the parents of the participants in 2015 revealed that the prevalence of type 1 diabetes was similar in both the placebo group and the vaccine group.
How rotavirus triggers type 1 diabetes?
Although there is no proven direct cause-and-effect association between rotavirus vaccination and type 1 diabetes, rotavirus-induced apoptosis (a type of programmed cell death) of pancreatic beta cells can be a vital causative factor for developing type 1 diabetes. In people with type 1 diabetes, beta cells, which are responsible for producing insulin, do not function properly, leading to a reduction in blood insulin levels and abnormal metabolism of glucose.
In addition, rotavirus peptides share some similar sequences with T-cell epitope peptides in the pancreatic islet autoantigens, which can trigger beta-cell autoimmunity. Studies have found that rotavirus infection is associated with a high serum level of islet autoantibodies, which is significantly associated with the onset of type 1 diabetes.
Science Daily. 2019. Lower risk of Type 1 diabetes seen in children vaccinated against 'stomach flu' virus. https://www.sciencedaily.com/releases/2019/06/190613095222.htm
Perrete, K.P. 2019. Association of Rotavirus Vaccination With the Incidence of Type 1 Diabetes in Children. JAMA Pediatrics. jamanetwork.com/journals/jamapediatrics/article-abstract/2721243
CDC. 2018. Rotavirus. https://www.cdc.gov/rotavirus/
Science Daily. 2019. Rotavirus infection may turn on type 1 diabetes. https://www.sciencedaily.com/releases/2019/10/191010161545.htm
Hemming-Harlo, M., et al. Rotavirus Vaccination Does Not Increase Type 1 Diabetes and May Decrease Celiac Disease in Children and Adolescents. Pediatr Infect Dis J. https://doi.org/10.1097/INF.0000000000002281 .
Leonard C, et al. 2019. Does rotavirus turn on type 1 diabetes? PLoS. https://doi.org/10.1371/journal.ppat.1007965