From the beginning of the pandemic, doctors have been sharing anecdotal evidence, with surges in Covid cases being followed a few weeks later by a surge in diabetes diagnoses. One such trend was spotted across four NHS trusts in northwest London, where 30 under-18s arrived with new-onset Type 1 diabetes between late March and early June 2020. Normally, they would have expected between two and four. 

On social media, families whose experiences echo Danny’s are sharing their stories and urging for more investigation. 

It is common for patients to be diagnosed with diabetes after recovering from an infection, whether viral or non-viral. In many cases, the infection may have brought pre-existing diabetes to light by aggravating a patient’s sugar levels or simply by getting them admitted to hospital.

But in September, researchers at Weill Cornell Medicine in New York published research showing that Covid-19 can infect insulin-producing cells in the pancreas and reduce their ability to produce insulin – supporting the theory that an infection can actually trigger the onset of new diabetes. 

The blogger and influencer Simon Hooper, known as Father of Daughters, whose 10-year-old daughter was diagnosed with Type 1 last year, has been documenting their journey and shared the study with his followers in an emotional post, writing: “From day 2 of Marnie’s diagnosis we heard whisperings that it could be Covid related…today it seems we’re a step closer to proving that link. 

“On one hand, I’m happy I know the possible reason why this happened to a sporty outgoing confident kid who had no worries in life. On the other hand is a strange type of nonsensical parenting guilt. Guilt that we didn’t do enough to protect her or take Covid more seriously than we did already.” 

Last year, statisticians at the Office for National Statistics joined forces with scientists at University College London and the University of Leicester doctors to track more than 47,000 UK patients who were hospitalised with Covid before August 2020. Almost five percent of the patients were later diagnosed with diabetes, they found, and those who’d been hospitalised with Covid were 1.5 times more likely to develop diabetes than others of the same age and background. A separate study tracked almost 2,500 patients in China hospitalised with Covid, and found that about 2.4 percent went on to develop new-onset diabetes.

Scientists have previously suggested that the body’s immune system, in its response to the Covid 19 virus, may mistakenly attack the cells of the pancreas that help to maintain normal glucose levels, triggering Type 1. But the new research suggests that the problem is caused by the virus itself attacking the cells involved in glucose production. 

“People normally think of Covid as a respiratory disease, but the cells the virus can enter are not just the ones lining the respiratory system,” says Prof Franesco Rubino, a diabetes specialist at King’s College London. 

Even more worrying, he says, is the strange combination of symptoms some post-Covid patients are exhibiting. It suggests Covid-19 might not be triggering Type 1 diabetes or Type 2 diabetes – but a new, previously unknown form of the disease. “There are patients who develop severe acute ketoacidosis [when ketones build up in the blood to dangerous levels], which is a complication of Type 1 diabetes; or patients who develop severe insulin resistance, which is a typical issue of Type 2 diabetes. [It] looks like a mix of the two, suggesting the relationship with the new coronavirus and diabetes goes above and beyond the typical manifestation. [It’s] enough for us to be concerned about.”

He is leading the establishment of a global database of Covid-19-linked diabetes cases, to better understand the link.  whether the infection can cause a new form of diabetes, or trigger a stress response that leads to Type 1 or Type 2 diabetes.

His theory rings true to Danny, who says his son is not responding to the standard treatment plan for Type 1 diabetes. Jack has continued to experience “hypos” – where blood sugar levels become too low – which have caused him to lose consciousness at times. Bewildered doctors have been forced to reduce his insulin dosages to unusually low levels and have recommended further tests. “They keep telling me that this is how we treat Type 1 diabetes and I keep saying ‘But it’s not working’,” he says. “From what I can tell, Jack’s not Type 1 and not quite Type 2 – he’s in the middle.”

He says they dismiss his questions about a link between Covid and Type 1.

“If this was caused by Covid, and it has caused a different type of diabetes, we need to know more because it could mean it needs to be treated differently.”

Scientists caution that we are still in the early stages of research. “The growing evidence suggesting coronavirus might be triggering diabetes in some people is concerning, but there’s still a lot more to learn,” says Dan Howarth, head of care at Diabetes UK. “Research is ongoing and it’s important we gain a full understanding. Some diabetes symptoms, like fatigue, may appear similar to those brought on by long Covid and it could be easy to mistake one for the other. If you’re experiencing any symptoms of diabetes – whether you’ve had coronavirus or not – you should seek help from your GP.”