A new vaccine developed by Finnish and Swedish researchers that targets six strains of enterovirus and could have a profound impact on the rates of type 1 diabetes.
The viruses in question all belong to the Coxsackie B (CVB) subgroup. Infection by these common viruses is theorized to be one of the leading factors in the development of type 1 diabetes in predisposed people.
Researchers hope that inoculation with the vaccine might remove this pathway to T1D development and significantly lower the rates of this increasingly common condition.
The Role of Viruses in T1D Development
The cause of type 1 diabetes is not well understood.
We know that there is a genetic component, as the condition tends to run in families. But we also know from studying family trees and identical twins, that the development of this disease is affected by environmental conditions as well.
One of the leading theories behind the development of type 1 is that infection with specific viruses may cause a person’s immune system to attack it’s own beta cells.
Not only have certain viruses been found in the pancreatic tissue of deceased diabetics, but viruses collected from the blood of newly diagnosed patients have shown the propensity to induce human islet cell destruction in vitro.
Despite numerous studies backing this virus theory, scientists still do not have a complete understanding of how viral infections may trigger this type of autoimmune reaction.
It’s possible that viruses that enter the pancreas may cause damage to the beta cells which in turn causes the immune system to attack these cells. Or, it may be possible that certain viral infections create the right conditions needed for hereditary autoimmune dysfunction to begin.
There is also significant evidence that the timing of these types of viral infections may play a role in how the immune system reacts. In fact, some studies have shown that the same virus can expedite the development of type 1 diabetes when the infection occurs during certain time periods while preventing the disease from developing when it occurs during other periods of life.
Enteroviruses, specifically CVB, are the type of viruses most commonly associated with the development of diabetes. Siblings who develop the condition have a much higher rate of enterovirus infection than those that do not, while pregnant mothers with elevated enterovirus antibodies are more likely to have a child that develops type 1.
In some populations, the diagnosis rates of T1D even mirror the seasonal trends of enterovirus infection.
However, CVB isn’t the only viral type to be associated with type 1 diabetes. Rotavirus, mumps, cytomegalovirus, and rubella have also been linked to the development of the condition.
Potential Effects of a CVB Vaccine
Interestingly enough, one of the best ways to learn more about how viruses like CVB affect the development of T1D is by developing a vaccine against them.
Recently, a study comparing populations vaccinated for rotavirus against those not vaccinated found that the rates of type 1 were actually about the same between the two groups. (You can read more about his study here.)
This study appears to point to the conclusion that rotavirus may not be as central to the development of type 1 as we once thought.
Whether this same thing is true of all viruses remains to be seen. And studies of vaccines like the one in development for CVB will help shed light on this issue.
Currently, the Swedish and Finnish researchers have completed animal studies using the vaccine and are now working with American researchers to begin human trials to test the vaccine’s safety.
If the vaccine proves to be safe and effective in preventing CVB enterovirus infection, the next step will be to begin human trials with children with genetic risk factors for developing T1D.
The hope is that these trials will reveal that inoculated children develop diabetes at a much lower rate than the general population.
While unlikely, it is also possible that those who receive the vaccine will develop T1D at a higher rate. Or, potentially, at varying rates depending on when the vaccine was given. It is even possible that there may be no notable difference at all.
While the outcome of this upcoming study is uncertain, one thing we do know for sure is that the results, whatever they are, will shed much light on the role of viruses in the development of type 1 diabetes.