Millions of COVID patients still don’t have their sense of smell or taste, study finds

BOSTON - Many of the patients who lost their sense of smell or taste following a COVID infection still have not fully recovered those senses, according to a new study out of Massachusetts Eye and Ear.

Researchers at Mass Eye and Ear looked at the loss of olfactory and gustatory senses and estimated that about 25 per cent of Americans who had COVID-19 reported only partial or no recovery of taste or smell.

We wanted to quantify the national impact of smell disorders resulting from COVID," said Neil Bhattacharyya, professor of Otolaryngology at Mass Eye and Ear.

With this data we can understand, in big numbers, how many people lost their sense of smell or taste due to COVID infection and how many people never fully recovered those senses," Bhattacharyya added.

The researchers examined data from the 2021 National Health Interview Survey, which includes survey data from 29,696 adults.

In the NHIS data, COVID patients were asked about the severity of their symptoms, any loss of taste or smell, and their recovery of those senses.

The research team reported that about 60 per cent of surveyed participants infected with COVID experienced loss of smell and about 58 per cent experienced loss of taste.

The study found that around 72 per cent of patients fully recovered their sense of smell, but 24 per cent only had a partial recovery, and more than three per cent had no recovery.

Similarly, of those who experienced a loss of taste due to COVID, about 76 per cent fully recovered the sense, while 20 per cent only partially recovered, and more than two per cent did not recover at all.

The researchers estimated that almost 28 million Americans had been potentially left with a decreased sense of smell after a COVID infection.

Bhattacharyya said one of the motivations for the study was his patient who lost 50 pounds due to COVID-related smell loss.

The patient wasn't eating and became very sick and very depressed because of the loss of smell," Bhattacharyya said. When you hear about COVID-related smell loss, you think most people get it back and are fine. But there is a substantial number of people who don't recover it."

The value of this study is that we are highlighting a group of people who have been a bit neglected," Bhattacharyya added. Losing your sense of smell or taste isn't as benign as you may think. It can lead to decreased eating for pleasure and, in more extreme cases, it can lead to depression and weight loss."

The study also found that there's a correlation between COVID symptom severity and loss of smell or taste. As symptom severity increased, the percentage of patients with smell or taste loss also went up.

Moreover, the likelihood of smell and taste sensory recovery dropped with more severe COVID symptoms.