Surprising COVID-19 Aftermath: Millions Lost Their Sense of Smell

It’s hard to imagine millions of people going partially blind unnoticed. However, the sense of smell is much easier to overlook. People can live with a reduced sense of smell and never realize it. This condition can still create serious health and safety risks.

Millions of Americans may have lost their sense of smell unknowingly. COVID-19 can cause a partial or total loss of smell, called hyposmia or anosmia, respectively. Viruses disrupt the cells and receptors in nasal passageways. Sense of smell can recover, but it does not always return.

What Key Findings Showed Reduced Sense of Smell from COVID-19?

Researchers studied nearly 3,000 volunteers with a history of COVID-19 infection. They compared them with 569 participants who had never tested positive. On average, the smell tests took place nearly two years after infection.

Of the 2,956 people in the COVID-19 group, 1,393 thought they had smell issues. Tests confirmed that about 80 percent of them were correct. The remaining 1,563 believed they had no problems, but 66 percent actually did.

A surprising finding was that 60 percent of people without COVID-19 showed smell difficulties. Researchers say some may have been infected without realizing it. If these patterns reflect the global population, millions may have hyposmia without knowing.

How Did Researchers Link Smell Loss to COVID-19 Infection?

The study was supported by the National Institutes of Health. Loss of smell could indicate deeper neurological issues. Experts are calling for more routine testing and additional research. They hope to identify possible treatments for smell loss after infection.

Researchers used a test that included 40 unique smells. Eighty percent of those who noticed a difference in smell were correct. Data showed low scores on clinical scent detection tests. Twenty-three percent of affected participants had significant impairment or complete hyposmia.

Hyposmia is linked to several health problems. These include weight loss, reduced quality of life, and depression. An impaired sense of smell also prevents detection of hazards like spoiled food, gas leaks, and smoke. It can also signal early stages of diseases such as Parkinson’s and Alzheimer’s.

The study appeared in JAMA Network Open. It is the largest study to date measuring hyposmia and anosmia after COVID-19 using objective data. Participants included thousands of Americans in the RECOVER adult study. RECOVER is a federally funded program studying the long-term effects of COVID-19 infection.

The RECOVER adult study included participants aged 18 years and older. Baseline differences in smell function between men and women affected scoring categories. Each correct answer on the smell test earned one point. Scores between 34 and 40 for men and 35 and 40 for women were considered normal.

Scores between 30 and 33 for men and 31 and 34 for women indicated mild microsmia. Scores between 26 and 29 for men and 26 and 30 for women showed moderate microsmia. Scores between 19 and 25 for both sexes indicated severe microsmia. Any score below 19 in either sex represented total anosmia.

Smell capacity was measured using the University of Pennsylvania Smell Identification Test, or UPSIT. This test uses scratch-and-sniff cards with 40 different odors. Participants selected multiple choice answers for each sample.

What Connections Did Researchers Find Between Smell Loss and Brain Fog?

The study also included self-reports about thinking and concentration difficulties, often described as brain fog. Participants who reported brain fog completed a Neuro Quality of Life questionnaire. This eight-item survey measured cognitive function in daily life.

Nearly half of participants who had COVID-19 reported trouble thinking or concentrating. Among those with smell difficulties, 66.1 percent also had cognitive problems. This was more than twice the rate, 32.7 percent, of those who did not notice smell changes.

Conclusion

A recent study shows that COVID-19 has lasting effects on smell and cognition. Many people experience smell loss or brain fog without realizing it. Researchers urge routine testing and further research to prevent long-term harm.

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Logan Hamilton is a health and wellness freelance writer for hire. He’s passionate about crafting crystal-clear, captivating, and credible content that elevates brands and establishes trust. When not writing, Logan can be found hiking, sticking his nose in bizarre books, or playing drums in a local rock band. Find him at loganjameshamilton.com.