Millions suffer from ‘distorted sense of smell’ post COVID – study

Millions of people, including tens of thousands of Israelis who recovered from COVID-19, are likely suffering from “distortion of odors” or “hallucinating odors,” even if they recovered from the virus months ago, according to new research published by the Hebrew University of Jerusalem.

The study, conducted through an international association for the study of the senses of taste and smell called the Global Consortium for Chemosensory Research, found that during the course of the disease, incidents of parosmia – a condition in which certain odors smell different and often unpleasant – and phantosmia – a phenomenon of hallucinating odors that do not exist in reality – occurred in only about 10% of patients who lost their sense of smell. However, after recovery, the incidents increased significantly: 47% reported parosmia and 25% phantosmia.

The typical reports received for patients with parosmia are things such as, “There are things that now smell different and unpleasant” or “like chemicals.” Reports of phantosmia included reactions such as “Sometimes I smell a fire, which no one around me smells.”

“We still do not know why and how exactly this is happening,” said Prof. Masha Niv of Hebrew University’s Faculty of Agriculture, Food and the Environment, who led the study on behalf of the school.

“We still do not know why and how exactly this is happening,” said Prof. Masha Niv of Hebrew University’s Faculty of Agriculture, Food and the Environment, who led the study on behalf of the school.

The report was published late last month on MedRxiv and has not yet been peer reviewed.

According to her estimates, if there are about a million Israelis who recovered from the disease and about half of them lost their sense of smell, it is likely that tens of thousands continue to have a weakened sense of smell and/or suffer from one of these phenomena.

Worldwide, the estimate would be around seven million people.

“Disturbances in the sense of smell affect appetite, mental state and quality of life in general,” she told The Jerusalem Post, adding that prolonged loss of smell can also be associated with headaches and fatigue.

This specific study included around 1,400 people who were surveyed during, immediately after and up to 11 months after contracting the virus. The researchers found that between two and 11 months after the disease, 60% of women and 48% of men reported less than 80% of odor capacity relative to pre-disease.

Taste recovered more quickly and rarely persisted if smell recovered.

“From the outside, loss of smell may not appear to be such a big deal,” Niv said, “but it can be dangerous, such as if you cannot smell a gas leak. It also has a very big impact on mood, like if you are unable to smell things that are pleasant. Some people develop anxiety.”

Moreover, many people suffer from weight loss because they cannot smell food, which reduces their appetite.

She said the most important result of this study would be a clinical trial of how best to treat the phenomena because “right now, there is really not a gold standard of treatment,” since the issue was much more uncommon before COVID-19.”

The study followed people who got sick before vaccination. Niv said it is possible that symptoms could be less pronounced in people who got sick after vaccination, “but this is just an educated guess and not something that has been shown yet.”