Upon receiving a diagnosis of type 1 diabetes (T1D), many people have the same reaction: â€œBut why me?â€
Some people have T1D that runs in their family, while others have no idea how or why they received a diagnosis. Often, to their frustration, those questions go unanswered.
But some people can seemingly link their T1D diagnosis to a previous virus they had endured directly before their onset of T1D.
This makes sense, as T1D is an autoimmune disease. This means your bodyâ€™s own immune system mistakenly attacks its own insulin-producing beta cells. Although scientists donâ€™t know the exact causes or reasons why T1D develops, some researchers believe this haywire immune system reaction is the result of a virus triggering your bodyâ€™s defense system to go into overdrive.
Viruses are now one main hypothesis of the cause of T1D. In particular, coxsackievirus is on the rise in those with newly diagnosed T1D. That has led some to wonder if thereâ€™s a direct correlation between this virus, or any virus for that matter.
Read on for more about coxsackievirus, how it materializes in people, and what research has to say about its potential for causing T1D.
What is coxsackievirus?
Coxsackievirus is a virus thatâ€™s part of the enterovirus family, which lives in the human digestive tract. This enterovirus family also includes polioviruses, hand, foot, and mouth disease (HFMD), and hepatitis A virus.
This virus spreads easily from person to person, usually through human touch or on surfaces contaminated with feces. The virus can live for several days without a host, making it extremely easy to spread.
When thereâ€™s a coxsackievirus outbreak, itâ€™s most likely to affect babies and children younger than 5 years old, as itâ€™s easily spreadable in places such as daycare centers, schools, and summer camps. Youâ€™re most contagious the first week that youâ€™re sick, and the best preventive mechanism is hand washing.
Usually, infection with this virus results in these mild flu-like symptoms initially:
- poor appetite
- runny nose
- sore throat
- feeling tired
Many people have no symptoms at all, and most people recover without treatment. But sometimes the virus can trigger more serious conditions or reactions, such as with HFMD, where a blister-like rash may appear on your hands or feet or in your mouth.
Thereâ€™s no specific treatment for this virus, and antibiotics donâ€™t help with viral infections.
How can viruses trigger T1D?
When a virus invades your body, your immune system produces antibodies to fight off that infection. T cells are in charge of developing antibodies as well as fighting off the virus.
But if the virus has some of the same antigens (or substances that cause your immune system to produce antibodies against them) as your bodyâ€™s own pancreatic beta cells (in the case of T1D), the T cells sometimes start attacking your bodyâ€™s own beta cells.
This miscommunication is common and results in autoimmune diseases like T1D. Once all the beta cells have been destroyed, T1D is developed and diagnosed. This is why people sometimes receive a diagnosis of T1D a few months after recovering from a bad virus.
But it can sometimes take more than a year for your bodyâ€™s T cells to destroy the majority of your beta cells (sometimes people experience the â€œhoneymoon phaseâ€ of diabetes, where their pancreas is still producing a minimal amount of insulin), but that original viral infection is hypothesized to be a trigger in the development of T1D.
Not every virus can trigger this reaction ending in T1D. The virus must have antigens that are similar enough to the antigens in pancreatic beta cells. Those viruses include:
- B4 strain of coxsackie B virus
- German measles
Thereâ€™s mounting evidence that the coronavirus disease 19 (severe acute respiratory syndrome coronavirus 2) pandemic is causing a tidal wave of new T1D diagnoses to be received by both children and adults. But the full repercussions of the pandemic are yet to be seen.
What the research says about coxsackievirus and T1D
A 2018 study showed that kids exposed to enteroviruses are more likely to develop T1D.
The Environmental Determinants of Diabetes in the Young study found, through nearly 8,000 stool samples of children in the United States and Europe, an association between an exposure and infection with coxsackievirus. This study followed participants for 30 days or longer and focused on the development of an autoimmune reaction that can lead to a T1D diagnosis.
In a Finland-based study, researchers tested more than 1,600 stool samples from 129 children who had recently developed T1D. They also tested 282 children without diabetes for enterovirus RNA, a marker of previous exposure to infection.
Researchers also found 60 percent of the control group showed signs of prior infection (without diabetes), compared with 75 percent of the group with T1D.
They also found that children who developed T1D were exposed to the virus more than a year before their diabetes was diagnosed. Taking this lag time of viral infection to T1D diagnosis into account, the researchers believed that children with diabetes are exposed to three times more enteroviruses than children without diabetes.
Viral infections arenâ€™t the only hypothesized cause of T1D, but research is homing in on viruses as a common trigger. Studies have shown that even if pregnant people are exposed to enteroviruses, such as coxsackievirus, theyâ€™re more likely to give birth to children who eventually develop T1D.
What does this mean for potentially preventing T1D?
Researchers arenâ€™t exactly sure what the precise cause of T1D is, and the virus hypothesis is just one theory. Many people believe that T1D is caused by a mix of genetic and environmental factors and that the disease may just be finally triggered by catching a virus such as coxsackievirus or another enterovirus.
While preventing viral spread is always important, even if all enteroviruses were prevented, T1D wouldnâ€™t be prevented in everyone, but it would probably make a big difference.
Researchers are hopeful with new trials showing vaccines against enteroviruses could potentially prevent many new diagnoses of T1D, but they wonâ€™t prevent all people from receiving diagnoses of course.
While thereâ€™s no vaccine to prevent T1D, Dr. Denise Faustman, Director of the Massachusetts General Hospital Immunobiology Laboratory, is working on that research front. Her work focuses on the bacillus Calmette-GuÃ©rin (BCG) vaccine, traditionally used to prevent tuberculosis, and how it can help people with T1D. Specifically, this century-old BCG vaccine may boost a substance called tumor necrosis factor, which eliminates T cells and helps develop more beneficial cells called regulatory T cells.
If you have diabetes, this could help improve your blood sugar and A1C levels while lowering your insulin requirements even years after your initial vaccination. That research is expected to continue for at least several more years beyond 2022.
The exact causes of T1D arenâ€™t known. But research shows enteroviruses, and in particular coxsackievirus, may play a part in the development of this autoimmune condition. Most researchers believe it to be a mix of both environmental and genetic factors, with perhaps a viral infection trigger. Research remains ongoing, and the development of a coxsackievirus vaccine could go a long way in preventing people worldwide from receiving diagnoses of T1D in the future.