We all know that vaccines save lives by preventing diseases. But a new study from Australia provides some solid evidence that the rotavirus vaccine not only protects children against the deadly rotavirus infection but also against type 1 diabetes.
This post will take a look at the vaccine, diabetes, and what the study shows. Preventing type 1 diabetes is a lofty goal for researchers for a long time. Let’s see if the data is convincing.
What is diabetes?
Type 1 diabetes is an autoimmune disease which is characterized by autoreactive T lymphocytes (T-cells) that destroy pancreatic islet cells, which are critical to glucose metabolism by producing insulin. These lymphocytes mistakenly attack the islet cells as if they were a foreign body, as they do with a viral or bacterial infection.
In addition, regulatory T-cells (which are often called Tregs) modulate the immune system and would normally reduce the effect of an autoimmune attack. Tregs act like brakes that normally prevent the mistaken attacks, like on the pancreatic islet cells, without affecting the whole immune system. A branch of diabetes research has suggested that abnormal Tregs could be the key to finding treatments to reverse type 1 diabetes.
Once the pancreatic islet cells are damaged, they no longer produce hormones, especially insulin, that help regulate the levels of blood glucose. Without insulin, the blood glucose levels increase rapidly leading to long-term damage to eyesight, kidneys, limbs, heart and other organs.
It is not known what causes this autoimmune disease, although there is strong evidence that genetics is the most important factor. However, other things may be implicated, like vaccine-preventable diseases, which could be important co-factors in the development of the disease. Just to be clear, vaccines are not linked to type 1 diabetes.
Currently, there are no known cures for type 1 diabetes. The only treatment for the disease is regular injections of human insulin, manufactured from genetically engineered E. coli cultures. In addition, careful diet and lifestyle management help regulate blood glucose levels, although it cannot replace insulin injections.
Type 1 diabetes can be deadly if the uncontrolled blood sugar leads to a life-threatening condition called diabetic ketoacidosis. Without regular insulin injections, a patient has little chance of living beyond a short period of time, and even then it could be a horrifically painful demise.
Even then, poor glucose control can lead to long-term complications like blindness (diabetic retinopathy), neuropathy, cardiovascular disease, and many other conditions.
In case the reader is wondering, type 2 diabetes is a substantially different disease from type 1. Mostly, type 2 diabetics produce insulin, just an insufficient amount to regulate glucose levels, or their cells have become resistant to insulin because of lifestyle issues. There is almost no relationship between type 1 and type 2 diabetes, except they share the same symptoms of high blood sugar.
Rotavirus vaccine
Rotaviruses are the most common cause of diarrheal disease among infants and young children across the world. Nearly every child in the world is infected with one of the nine different species of rotavirus at least once by the age of five.
The virus is transmitted by the fecal-oral route usually from contaminated objects, foods, or unwashed hands. Rotavirus infection is mostly observed in infants and young children. However, even older children and adults are known to become infected with the virus.
The virus infects and damages the cells that line the small intestine, causing gastroenteritis, which some people incorrectly call the “stomach flu,” a disease that does not exist.
Rotavirus is spread easily in schools, daycare, and within houses. Good hygiene (handwashing) and cleanliness are important but are not enough to control the spread of the disease. You can be immaculately clean, but the virus just moves from person to person quickly and easily.
One of the primary issues with the rotavirus is that once a person has been exposed to infection, it takes about 2 days for the symptoms to appear. Thus, the virus can be easily passed between individuals before the infected child becomes symptomatic.
The complications of rotavirus infection are not minor. Children who get infected may have severe watery diarrhea, often with vomiting, fever, and abdominal pain. These symptoms can last for 3-8 days, during which the child has to be closely watched for dehydration and loss of appetite, dangerous conditions for infants and children.
Before the introduction of the vaccine in the USA in 2006, rotavirus infection caused significant morbidity among U.S. children, with an estimated 55,000–70,000 hospitalizations and 410,000 clinic visits annually. According to an analysis of 10 years of rotavirus infections in the USA before the introduction of the vaccine, rotavirus was estimated to be the cause of approximately 2.7 million (yes million) cases of severe gastroenteritis, 60,000 hospitalizations and 37 deaths annually.
Worldwide, more than 450,000 children under five years of age still die from rotavirus infection each year. Think about that–nearly one-half million children die from a disease that could be prevented by a simple vaccine, every single year.
In 2006, the rotavirus vaccine (see Note 2) was first included in the childhood vaccination schedule in the USA. Subsequently, there was a substantial, sustained decline in rotavirus circulation both nationally and regionally, as well as a shift in the epidemiology of this virus.
Rotavirus vaccine and type 1 diabetes
Previous studies have shown that rotavirus infections have been associated with the development of type 1 diabetes in children. Researchers have proposed that the infection triggers pancreatic cell death, which shuts down the production of insulin.
The study by Dr. Kirsten P Perrett et al., published in JAMA Pediatrics, hypothesized that if natural infections by rotavirus was a causative factor for type 1 diabetes, then immunization by the rotavirus vaccine would decrease type 1 diabetes over time. The researchers used publicly available data on the incidence of diabetes in Australian children before and after the rotavirus vaccine was introduced in 2007.
Perrett et al. found a 14% drop in type 1 diabetes in children age 0 to 4, but no change in children 5 to 14 years old. It is likely that the older group included children who were born before the introduction of the rotavirus vaccine. It must be given prior to exposure to the virus to have any protective effect. Once the infection occurs, it might lead to the destruction of pancreatic cells.
The authors concluded that:
We report what is to our knowledge the first evidence of a decline in the incidence TID (type 1 diabetes) after the introduction of oral RV (rotavirus) vaccine into a routine immunization schedule. These findings have prompted our team to do a case-control linkage study to further explore the association between RV vaccination and T1D incidence in Australian children.
Although this study clearly shows a reduction in type 1 diabetes in children after the introduction of the rotavirus vaccine, it is still a very simple type of epidemiological study. Moreover, it cannot exclude confounders – for example, maybe there was some other change in healthcare in Australia during that time that could have lead to a reduction of type 1 diabetes.
The researchers also indicated that a case-control study, which would look at the type 1 diabetes incidence in a population that received the rotavirus vaccine versus one that didn’t. That would provide us with more robust evidence of a direct causal link.
However, this study is very important. Since we have very powerful evidence of a biologically plausible link between rotavirus infection and the development of type 1 diabetes, this study gives us robust confirmation that the vaccine, by stopping the rotavirus infection, may reduce the risk of type 1 diabetes significantly.
Type 1 diabetes is a dangerous disease for children. Since the rotavirus vaccine is very safe, I would suggest that making certain that children don’t get either the infection or the possible diabetes complication makes the choice in favor of the vaccine easy.
Notes
- There are other types of diabetes, like gestational diabetes and diabetes insipidus, which do not share the same pathophysiology as type 1 and type 2 diabetes, although they may share some of the same symptoms.
- Dr. Paul Offit co-developed one of the rotavirus vaccines, RotaTeq. We should thank him for helping prevent the deaths of hundreds of thousands of children. The end.
Citations
- Honeyman MC, Coulson BS, Stone NL, Gellert SA, Goldwater PN, Steele CE, Couper JJ, Tait BD, Colman PG, Harrison LC. Association between rotavirus infection and pancreatic islet autoimmunity in children at risk of developing type 1 diabetes.Diabetes. 2000 Aug;49(8):1319-24. PubMed PMID: 10923632.
- Perrett KP, Jachno K, Nolan TM, Harrison LC. Association of Rotavirus Vaccination With the Incidence of Type 1 Diabetes in Children. JAMA Pediatr. 2019 Jan 22. doi: 10.1001/jamapediatrics.2018.4578. [Epub ahead of print] PubMed PMID: 30667473.
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