Introduction

The connection between mumps and the development of type 1 diabetes is a topic worthy of insight and understanding for patients, healthcare providers, and researchers. This article explores the mechanism by which the mumps viral infection may trigger the onset of Type 1 diabetes, via scientific research evidence and clinical observations. 

The viral infection mumps was known for its formerly common pattern of contagious disease in children, until the introduction of the MMR (Measles, Mumps & Rubella) vaccines. The mumps, which primarily affects the area beneath the ears, have been associated with an increased risk of developing Type 1 diabetes. This is caused by an autoimmune response, triggered by the virus as theorised by researchers. In this case, the autoimmune response is triggered as the body’s immune system mistakes the insulin-producing cells in the pancreas as foreign organisms and attacks them. This response is a key factor in the development of Type 1 diabetes.¹

Though the relationship between mumps and the development of Type 1 diabetes has been answered, there remains more to unpack. The complex relationship between the two includes the underlying mechanisms by which the autoimmune response occurs, risk factors and prevention and health strategies. Keep reading for a greater understanding of how exactly mumps can contribute to the development of Type 1 diabetes and how to protect yourself and loved ones.

Mumps

As mentioned earlier,  mumps is a viral infection that primarily affects the parotid glands, which are responsible for saliva production, causing swelling, thus resulting in a distinctive “hamster face” appearance as depicted in Figure 1. This swelling can occur in one or both parotid glands, so one or both sides of the face are swollen.¹ Although mumps is heavily linked to the swelling of glands, there are a few other common and noteworthy symptoms:

• Headaches
• Joint pain
• High temperature

All of these may develop shortly before the glands swell.

Though not usually serious, it does have quite similar symptoms to more serious infections such as glandular fever or tonsillitis; therefore, upon suspicion of a mumps viral infection, contact your GP for an accurate diagnosis to be made. Swelling observation, tonsil position within the mouth and a temperature check are some preliminary examinations on which the GP usually makes a diagnosis based on.

The mumps virus is spread similarly to that of the common cold and flu in that infected bodily fluids, such as saliva droplets, can enter the nasal or oral pathways via inhalation or be picked up from surfaces. Peak contagiousness falls in the few days before symptoms occur and a few days afterwards.

Figure 1: Depiction of mumps viral infection and its resulting swelling of the parotid gland in comparison to a normal-sized gland. (Taken from Informedhealth.org²)

Type 1 diabetes

Type 1 diabetes, as many would know, involves issues related to levels of sugars (glucose) and insulin. It is a disease in which the glucose level becomes too high, due to a lack of or reduced release of the hormone insulin. Insulin controls the blood glucose levels, and thus, in  Type 1 diabetes, where there is a lack of insulin, insulin must be taken every day to maintain control of blood glucose levels.

A common thought when discussing diabetes is the underlying causes, such as weight or age, but these are linked with Type 2 diabetes and not Type 1.³ 

It is worth noting  the varying symptoms associated with Type 1 Diabetes:

• Urinating more than usual, especially at night
• Increased feeling of tiredness
• Increased thirst
• Unintentional weightless
• Recurring thrush despite treatment
• Fruity-smelling breath
• Blurred vision
• Cuts and wounds that are not healing

At the sight of any of these symptoms, book a GP appointment for diagnosis. The testing commonly consists of a urine test and a blood glucose level check.  Based on the preliminary tests, if diabetes is confirmed, a recommendation for a hospital assessment shall be made, where a complete blood test is done. If the results show a diagnosis of Type 1 diabetes, then proper guidance is given as to how to manage the disease, like teaching how to test blood glucose at home and how to inject insulin as safely and as pain-free as possible.⁴

Due to the autoimmune nature of the disease, there is a lack of the hormone insulin. Insulin-producing cells, also known as beta cells, are mistakenly destroyed by the immune system, as it identifies these cells within the pancreas as foreign or “non-self” (meaning not of the host body). The destruction of these cells results in an absence or depletion of insulin, thus resulting in diabetes.⁵ It’s believed that this process of autoimmunity festers for years; in turn, there are people at risk of developing diabetes without a diagnosis at present.

Understanding the relationship between mumps and Type 1 diabetes is critical, as one is notably contagious and the other is often at work without the patient's knowledge. Together, they result in the speeding up of the possibly pre-existing autoimmunity amidst the beta cells, resulting in the onset of Type 1 diabetes. With the widespread infection of mumps before the development of the MMR vaccine, and continual outbreaks following the development of the vaccine, understanding the relationship it has with Type 1 diabetes allows for greater insight into the virus and the onset of the disease. The current knowledge of autoimmune disease triggers and their mechanisms must be enhanced alongside the improvement of informed public health strategies. All of these support better prevention, diagnosis and treatments for the vulnerable population. 

Research on the connection between mumps and type 1 diabetes

As stated, the most common hypothesis supporting the link between mumps and Type 1 diabetes is that the viral infection via the mumps virus either enhances a pre-existing autoimmunity process or onsets the disorder and response as noted in the damaged pancreatic beta cells..⁶

Type 1 diabetes is an autoimmune disorder where the insulin-producing beta cells are destroyed, which may be due to an underlying genetic cause. In short, white blood cells that are programmed to attack foreign organisms and pathogens become autoreactive white blood cells in Type 1 diabetes. These recognise varying pancreatic antigens such as insulin, and thus attack the beta cells that produce them. How these beta cell antigens become immunogenic has been a core focus of varying research, and the conclusion that has been drawn is that the major driving force is the infiltration of autoreactive T cells occurs where the beta cells are located (islets of Langerhans).⁶ Research then revealed the consideration of other contributing factors in disease development, which include the environmental influences in the development and progression of the viral infection.

Amidst the varying research conducted, a 2008 paper⁶ reported that though many viruses had been noted for their association with Type 1 diabetes onset, including the mumps virus. However, at the time, only the congenital Rubella Syndrome had conclusive connections to disease onset and progression. Following this, a 2024 paper,⁷ noted that though historically linked to insulin-producing beta cell damage and autoimmunity, mumps at present has limited research on its relationship with and the development of Type 1 diabetes. It was concluded that the mumps viral infection is capable of affecting immune responses where there is persistent infection.⁷  

Vulnerable populations

As previously mentioned, in regard to mumps infection, the vulnerable population is mainly children and some younger adults or adolescents who did not receive the MMR vaccine in their childhood. In regard to Type 1 diabetes, adolescents are the population with the highest incidence.^1,8

Preventative measures

In light of the vulnerable populations, a major preventive measure in both mumps infection, thus in turn the ability to onset and progress Type 1 diabetes, has been the introduction of the MMR vaccine. This preventive measure proved most effective in those born after its introduction in 1988. Adults born before the vaccine most likely were infected with mumps as children, but it is common that once infected with the mumps virus, they develop lifelong immunity against further mumps infection. Adults born between 1988-1990 are also less likely to have been infected as children compared to their older adult counterparts, despite probably not receiving the vaccine, as the overall mumps infection saw a decrease upon its introduction in 1988.¹

As there has been a great decrease in mumps infections since the introduction of the MMR vaccine, it is a viable and effective preventative measure in not only the incidence of mumps but also in the cases of Type 1 diabetes onset or progression, related to the viral infection.  

Summary

The primary need for understanding the relationship between mumps and the development of Type 1 diabetes is for educated and effective improvements and implementations of public health strategies, prevention enhancements and informed and improved treatment approaches. The connection between the virus and the disease is centred around the hypothesis that the viral infection may trigger or further promote an autoimmune response resulting in the destruction of the pancreatic insulin-producing beta cells. In spite of varying evidence and conclusions, the hypothesis that mumps does in fact initiate or quicken Type 1 diabetes’ underlying autoimmune process highlights the importance of MMR vaccination. The reduction of mumps incidence, thus in turn, may potentially decrease the onset of Type 1 diabetes. Extended and steady research is essential to fully explain this relationship, ensuring that public health policies effectively address these interlacing health issues.