Smell and taste loss differ with COVID-19 versus colds; Blood-vessel cells break off in severe COVID-19

Smell and taste loss differ with COVID-19 versus colds; Blood-vessel cells break off in severe COVID-19

The smell and taste impairments associated with the novel coronavirus differ from what people experience with a cold and is likely linked with nerve damage, a new study suggests.

Researchers gave smell and taste tests to 10 COVID-19 patients, 10 people with bad colds and 10 healthy people.

Unlike people with colds, COVID-19 patients could breathe freely and did not tend to have a runny or blocked nose.

Furthermore, they could not detect bitter or sweet tastes, and they had more severe taste impairment overall.

The original SARS virus, which caused a global respiratory disease outbreak in 2003, can enter the brain, the researchers noted in a report on Wednesday in the journal Rhinology, and they said their new findings lend weight to the hypothesis that COVID-19 also infects the brain and central nervous system.

“It is particularly interesting that COVID-19 seems to particularly affect sweet and bitter taste receptors, because these are known to play an important role in innate immunity,” study co-author Carl Philpott of the University of East Anglia’s Norwich Medical School in Britain said in a statement.

“More research is needed to see whether genetic variation in people’s bitter and sweet taste receptors might predispose them to COVID-19.”

Blood-vessel cells break off in severe COVID-19

Blood clots, a well-known complication of COVID-19, are at least partially due to damage to the endothelium, or blood vessel lining, researchers have suspected.

Now a study confirms that severe COVID-19 is linked with “marked and widespread” injury to blood vessels, with high numbers of cells that usually comprise blood-vessel linings becoming detached and found circulating in the blood.

As reported on Wednesday in the Journal of Infectious Diseases, researchers in France measured levels of so-called circulating endothelial cells detached from injured vessels in 99 hospitalized COVID-19 patients.

Levels were significantly higher in patients in intensive care units and were correlated with patients’ levels of inflammatory proteins, illness severity scores and length of hospitalization.

The researchers tested each patient’s blood only once, so they could not discern how injuries to blood vessel linings might evolve as the illness worsens.

Still, they said, the blood vessel lining plays key roles in maintaining vascular stability and function, delivering blood to organs and regulating blood clotting, and any endothelial injury would impair those functions. — Reuters