A new study says it might take up to a year for the ability to smell to return after COVID-19.

Anosmia – the partial or total loss of smell – has been one of the defining symptoms of COVID-19.

The study, published in the JAMA medical journal, says anosmia could last up to a year. For the study, a team of medical researchers analyzed 97 patients with acute smell loss lasting more than seven days after a positive COVID-19 diagnosis.

Of the 97 participants, 51 underwent both subjective and objective olfactory tests, the study says, meaning they were surveyed about their sense of smell and tested to corroborate their responses.

These 51 patients took surveys every four months over the course of a year asking about their ability to smell.

The participants rated their sense of smell according to how strong they believed it to be at each four-month interval.

At the four-month mark, about 45 percent of the 51 patients reported having their full sense of smell back, according to the study.

A majority, about 53 percent, said they only regained their sense of smell partially. The remaining 2 percent indicated they felt no change in olfactory strength.

At the eight-month interval, about 96 percent of the 51 patients reported full recovery.

Two patients, or about 4 percent, continued to report a decreased sense of smell at the one-year mark.

About 28 percent of the 46 patients who underwent only the subjective test – the surveys – reported "satisfactory recovery" at the four-month mark, the study says.

The remaining participants reported the same by the year mark.

"Persistent COVID-19–related anosmia has an excellent prognosis with nearly complete recovery at 1 year," the medical researchers said.

"As clinicians manage an increasing number of people with post-COVID syndrome, data on long-term outcomes are needed for informed prognostication and counseling."

This article was originally published by Business Insider.

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