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The First Sure Sign You Have COVID, Say Doctors

A new study finds that Amazon reviews might pinpoint a common symptom.
FACT CHECKED BY Emilia Paluszek
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By now, you likely know that one of the first—and most unusual—signs of the unusual disease known as COVID-19 is a loss of the sense of smell (anosmia). A new study has found there may be an unusual—and thus, perfectly modern—way to measure its spread: Through Amazon reviews of a particular product.

First, about that loss of smell being an indicator of coronavirus: An analysis of studies found that 77% of coronavirus patients reported a loss of smell when they were first tested for COVID-19 and that it was one of the earliest signs of the disease. Another study found that loss of smell was a more reliable indicator of COVID-19 than better-known symptoms such as fever and cough. Read on, and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had Coronavirus.

Why COVID causes loss of smell

Scientists aren't sure why COVID-19 causes anosmia, but some theories are shaping up. "We have been researching this data for less than a year. Still, so far, it suggests that the primary attack of the coronavirus is in the nose, in the nasal epithelium, which is the skinlike layer of cells in charge of expressing odors," says Dr. Leo Nissola, MD. "It seems like the virus assaults support cells and stem cells in the nose."

He adds: "These cells maintain the balance and signal the brain. In some patients, when infected with COVID, that balance is disrupted, and that leads to a shutdown of neuronal signaling, and therefore of smell. The cells also provide support to sustain the cilia on the nose where receptors that detect odors are located. If the virus disrupts those cilia, you lose the ability to smell."

A July CDC study determined that this symptom lasts eight days, on average, but some people can experience it for weeks. 

RELATED: 7 Tips You Must Follow to Avoid COVID, Say Doctors

Amazon reviews = diagnostic tool?

And as for diagnosis via Amazon: A study of Amazon reviews of scented candles may correlate to COVID-19's spread. According to the Washington Post, a Harvard researcher looked at Amazon reviews and ratings of scented versus unscented candles from 2017 to 2020, finding that buyer satisfaction with scented candles dropped off more precipitously than that of unscented candles and seemed to correlate with surges of coronavirus. 

Apparently, more buyers complained about scented candles having no scent, or an unsatisfactory one. "Negative reviews spiked during the pandemic's first wave in the spring, dropped off during the summer and are surging again as the country shatters records for new infections," the Post reported this week.

As for yourself, do everything you can to prevent getting—and spreading—COVID-19 in the first place: Wear a face mask, get tested if you think you have coronavirus, avoid crowds (and bars, and house parties), practice social distancing, only run essential errands, wash your hands regularly, disinfect frequently touched surfaces, and to get through this pandemic at your healthiest, don't miss these 35 Places You're Most Likely to Catch COVID.