Covid Heart, Covid Brain, Covid Diabetes?

People affected by post-acute or long covid (July 2020)

Published: March 24, 2022
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The latest on covid disease, long covid, and covid treatment.


The issue of post-acute and chronic covid health issues in the general population is  an important one because the potential public health impact may be significant. Unfortunately, it’s also an issue that has been plagued with many low-quality studies and media fearmongering.

Covid Heart

In the summer of 2020, a German MRI study, published in JAMA Cardiology, claimed that 60% to 80% of people showed signs of heart inflammation or heart injury two months after mostly mild covid. The study received over one million views and over 700 citations, but skeptical cardiologists quickly pointed out that the MRI interpretation was not consistent with blood markers. The skeptics were correct: later studies found that heart inflammation after covid is not more frequent or more severe than after influenza or the common cold.

Instead, it was covid mRNA vaccines that caused an unprecedented wave of serious heart inflammation and cardiac arrest in young people (especially males). Curiously, the media exaggerated the non-existent “covid heart” but downplayed the very real “covid vaccine heart”.

See also: Setting the record straight: There is no ‘Covid heart’  (Stat News, May 2021)

Covid Brain

More recently, a British MRI study, published in Nature, claimed to reveal “substantial changes in the brain after (covid) infection”. Specifically, the study observed a reduction of grey matter in olfactory-related brain regions (i.e. regions related to smell and taste) of 0.7% on average in covid-infected people compared to controls (compared to an average annual loss of 0.2% to 0.3%). Many media outlets reported that “covid will make your brain shrink”.

But already back in June 2021 (when the preprint of the study appeared), UCL professor of Computational Biology, Francois Balloux, noted that the MRI study established only correlation, not causation: for instance, it is possible that the neurological changes (if real) were caused not by the virus itself – there is still no evidence that SARS-CoV-2 is infecting the brain – but by neural adaptation in response to the transient loss of the sense of taste or smell.

Indeed, the British study did not distinguish between covid patients with and without loss of taste or smell, nor could it establish if these neurological changes were permanent or transient. The study didn’t show any actual clinical symptoms, either. Thus, additional studies will be needed to establish if these preliminary findings are both real and clinically relevant.

On the other hand, a study recently published in Brain, Behavior and Immunity found “neuro­inflammation in non-infected individuals during the COVID-19 pandemic”, likely caused by persistent stress or anxiety, a condition the authors termed “the pandemic brain”.

Read more: Does a Mild Case of Covid Really Damage Your Brain? (Bloomberg, March 2022)

Covid Diabetes

Several studies have proposed that covid infection may increase the risk of diabetes. In January 2022, a US CDC study proposed that covid increased the risk of diabetes in children, but the study was designed so poorly that is was rejected by many scientists.

A German study found that diabetes type 1 did indeed increase in children during the pandemic, but it did so both in infected and in uninfected children. Other studies found a dramatic increase in childhood and adult obesity during the pandemic, a known risk factor of type 2 diabetes.

More recently, a US veterans study, published in Lancet Diabetes, and another German study, published in Diabetologia, again found that the risk of diagnosed type 2 diabetes (but not type 1 diabetes) increased by about 20% to 40% after covid. The risk increase was strongly driven by covid severity, BMI/obesity and pre-existing pre-diabetes. In the German study, the risk apparently increased only about 8 months after covid infection.

In general, it is conceivable that covid-induced inflammation, especially in obese or pre-diabetic individuals, could increase the risk of diabetes. Nevertheless, the cardiologist who first debunked the “covid heart” study remains skeptical: “This grift is getting ridiculous. Isolate individual “diseases” from your data set, ignore the proper controls that you have already run, and drip out minimum publishable units for maximum fear induction.”

It should also be noted that covid vaccination, too, may induce diabetes and other metabolic or cardiovascular conditions, as several case studies have already shown.

See also: New Research Shows Higher Risk of Developing Diabetes After Covid-19 Infection (WSJ, March 2022)

Other recent “long covid” studies

A large US study recently published in Nature Medicine found that covid patients had an increased risk of several cardiovascular conditions and events one year after infection. The increased risk affected mostly (but not exclusively) covid patients who had been hospitalized or in ICU. The study did not consider the risk after covid vaccination or after other respiratory infections.

A Swiss long covid study recently published in the Journal of Internal Medicine found that, one year after covid infection, about 30% of 1,500 covid outpatients reported “functional impairment”, compared to about 6% in the control group. This included fatigue (16% vs. 3%), shortness of breath (9% vs. 1%), headache (9.8% vs. 1.7%), and difficulty concentrating (7.5% vs. 2.5%).

A German study (preprint) covering about 12,000 people found that, after about 9 months, about 27% of infected people (mostly outpatients) suffered from “post-covid syndrome”, which included, most notably, rapid physical exhaustion, shortness of breath, concentration difficulties, chronic fatigue, memory disturbance, and altered sense of smell (see diagram below).

These are very substantial figures that may indicate a significant public health burden.

A young British long covid patient, who was one of the first in the world to have been diagnosed with significantly reduced lung perfusion and gas exchange, recently reported a very low venous oxygen saturation of only about 25% instead of about 65% despite normal arterial oxygen saturation (about 98%), a highly unusual and still unexplained finding. Since her “mild covid infection” in early 2020, the young and previously very healthy woman experiences “fatigue, breathlessness and heart burn” after walking and talking.

Studies on long covid after vaccination indicate that vaccination may reduce the risk of long covid especially in older people (by preventing severe acute covid), but may not be able to substantially reduce the risk of long covid after mild acute covid in young people (as vaccination cannot prevent mild covid). In addition, vaccination may itself cause long covid-like symptoms. Thus, covid vaccination continues to be indicated mostly for people at high risk of severe acute covid.

Read more: Post-Acute Covid and Long Covid (SPR)

New covid treatment studies

The British Recovery trial found anti-inflammatory and immune-suppressive rheumatoid arthritis drug Olumiant (baricitinib) to reduce mortality by about 20% in already hospitalized covid patients.

The American Together trial found novel single-dose therapeutic Peginterferon Lambda to reduce the risk of covid hospitalization and emergency room visits by about 50% in a predominantly vaccinated population, and to reduce the risk of death by 60%. Peginterferon Lambda is a late-stage type III interferon (IFN) that works by stimulating the antiviral response in the respiratory tract.

Concerning ivermectin, the results of several high-quality studies are still outstanding. Several previous high-quality studies found a non-significant mortality benefit, possibly due to the known anti-inflammatory effect of ivermectin.

Annex: “Post-Covid Syndrome” (German Study)

“Post-Covid Syndrome” (German Study)

See also

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