Researchers have shown how smell loss associated with the Covid-19 infection differs from what you might typically experience with a bad cold or flu. The main differences found are that, although Covid-19 patients also lose their sense of smell, they can breathe freely, do not tend to have a runny or blocked nose, and they cannot detect bitter or sweet tastes. These findings, published in the journal Rhinology, lend weight to the theory that Covid-19 infects the brain and central nervous system.

"The loss of smell and taste is a prominent symptom of Covid-19, however, it is also a common symptom of having a bad cold," said study lead author Carl Philpott from the University of East Anglia in the UK. "We wanted to find out exactly what differentiates Covid-19 smell loss with the kind of smell loss you might have with a cold and blocked-up nose," Philpott added. The research team carried out smell and taste tests on 10 Covid-19 patients, 10 people with bad colds and a control group of 10 healthy people -- all matched for age and sex.