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Home » Do COVID vaccines cause diabetes? Another anti-vax myth

Do COVID vaccines cause diabetes? Another anti-vax myth

Here we go again, anti-vaxxers are now claiming that COVID-19 vaccines cause type 1 or 2 diabetes. I don’t think I’m exaggerating when I say that each new day brings a new claim about COVID-19 vaccines that is easily debunked.

At least I can find the reason behind this claim, albeit requiring some logic and science contortions. However, typical of anti-vaxxers, they take it several steps too far.

Anti-vaxxers have tried and failed, to link vaccines with type 1 diabetes. And we know that COVID-19 itself might increase the risk of type 1 diabetes. But is there a link between COVID-19 vaccines and either type of diabetes? No.

Photo by Ella Olsson on Unsplash

What is diabetes?

There are several forms of diabetes, but the ones that are the most common are type 1 or type 2 diabetes mellitus. Although they have similar names, they have separate etiologies and pathophysiologies.

In the most simple terms, all forms of diabetes have a common sign – excess blood glucose levels.

In a normal person (actually, blood glucose control is the same from lobsters to fish to dogs to humans), insulin is produced by specialized cells in the pancreas in response to increased levels of glucose in the blood, usually after a meal. Insulin signals cells to store sugar until it’s needed.

When the blood sugar gets low, the pancreas produces another hormone called glucagon, which signals cells to release stored glucose.

That is a very simplified description of a complex system. The point is that the body strives to maintain a constant blood glucose level so that all of your other systems, cells, and organs can function in between meals.

It is an autoimmune disease, where the immune system attacks the insulin-producing cells, destroying the ability to produce insulin. This causes the control mechanism of blood sugar to break down leading to high blood glucose levels.

At this time, there are no cures, but generally, a type 1 diabetic who maintains good blood glucose control with diet, exercise, and proper doses of insulin can live a long time.

We do not know what causes type 1 diabetes, but it is probably related to an infection that causes the immune system to attack the pancreatic cells. Generally, the disease starts during childhood, but some forms can begin when someone is in their 30s.

On the other hand, Type 2 diabetes (T2DM) is a completely different disease. While type 1 diabetes has a clear cause, T2DM is much more complicated. Many people like to blame obesity and Big Macs for T2DM, but that’s vastly oversimplifying the etiology of the disease.

Type 2 diabetes isn’t one disease, it is several different diseases that are lumped together. In general, they all result in some combination of obesity, inactivity, diet, and genetics. There are fit, thin marathoners who have developed T2DM, and there are obese, inactive people who consume Big Macs several times a day who do not get the disease.

However, lifestyle (obesity, activity, and diet) are the largest and most powerful risk factors for type 2 diabetes. And, as opposed to type 1, type 2 is mostly preventable and reversible, and the body still produces insulin. It also is usually identified in adults, usually in their 40s and 50s.

The pathophysiology of type 2 diabetes is quite complex, and describing it is beyond the scope of this article. Blood sugar control goes awry as the insulin signals start to be “ignored” by cells, and so instead of storing the sugar, the glucose remains in the blood.

Even though both types of diabetes are completely different diseases, they have the same major sign — high blood glucose levels. And that’s what leads to long-term diseases such as cardiovascular disease, immunosuppression, kidney disease, neurological disease, and much more. Uncontrolled blood sugar will not kill someone immediately (unless it’s extremely high), but it kills over many years.

Photo by Quinten Braem on Unsplash

COVID-19 vaccines and diabetes

It is clear how this myth arose – many vaccines do cause a temporary increase in blood sugar levels for a bit of time after receiving the vaccine. In response to an infection or a vaccine, the immune must mount an attack. In doing so, the immune system requires more energy, so a signal is sent to release stored glucose to “feed” the immune response.

In nondiabetic individuals, this increase in blood sugar is very short, maybe lasting 1-2 hours. However, for those individuals with existing type 1 or 2 diabetes, it is possible that the COVID-19 vaccines can increase blood sugar levels for several days.

Temporary increases in blood sugar are not a cause for concern for diabetics unless it lasts for a long period without control. I could write a 50,000-word article debunking all of the myths about diabetes, but one is that diabetics live on the edge of death every single day and their blood sugar levels aren’t perfect. That’s just not true.

Unfortunately, COVID-19 is a serious disease for diabetics — they are much more susceptible to severe complications from COVID-19. So, a temporary uptick in blood sugar levels after getting one of the COVID-19 vaccines is a minor price to pay for diabetic patients.

I think this blood glucose increase led to the myth that the vaccine causes diabetes. It does not. Individuals who do not have diabetes probably wouldn’t notice the 1-2 hour increase in blood sugar levels, unless they’re testing their blood sugar every few minutes. The increase probably would be no different than what would be observed after eating an ice cream cone.

On the other hand, diabetics may see a temporary increase in their blood sugar levels post-COVID-19 vaccination. This is not dangerous. Most diabetics are quite capable of dealing with these increases by contacting their physician and managing it carefully for a few days.

But let me be clear. There is no evidence that COVID-19 vaccines cause type 1 or 2 diabetes — I could not find any peer-reviewed, published article that supported the hypothesis that any of the COVID-19 vaccines are linked to type 1 or type 2 diabetes. None.

Yet, I could find several articles that show a strong link between COVID-19 itself and diabetes. In other words, COVID-19 vaccines probably prevent excess cases of diabetes.

I think this myth started with just a bit of plausibility — the vaccine causes a temporary increase in blood glucose levels. But it goes off the rails because that increase does not affect individuals who are not diabetic, and only has a temporary effect (just a couple of days) in those who are diagnosed with type 1 or type 2 diabetes.


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