This COVID Symptom Comes Before Fever, Says Study

When stores, restaurants and gyms reopened after the coronavirus pandemic's first wave, many did so with body-temperature checks for employees (and, often, customers), in an attempt to provide early detection of the virus and stem its spread. Fever, it was believed, was a reliable indicator of COVID-19 infection.

Months later, some experts are saying that may not be so—and that another symptom is an earlier, more consistent tip-off: Loss of smell. Read on for more, and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had Coronavirus.

What symptom might come before fever?

Some coronavirus patients never develop a fever. But a new analysis of studies found that 77% of coronavirus patients reported a loss of smell when they were tested, The Philadelphia Inquirer reported Monday.

"It is one of the earliest symptoms, and it is certainly earlier than fever," said Nancy Rawson, a biologist and associate director of the Monell Chemical Senses Center in Philadelphia, which participated in the study. "Smell loss alone predicts diagnosis better than a fever."

Rawson's company is developing a scent test it hopes can be used for early COVID detection. In the meantime, to test yourself at home, you can use fragrant items like coffee, perfume, toothpaste, basil or rosemary, she said.

Other studies show smell loss common

"Temporary loss of smell, or anosmia, is the main neurological symptom and one of the earliest and most commonly reported indicators of COVID-19," reported Harvard Medical School in late July. "Studies suggest it better predicts the disease than other well-known symptoms such as fever and cough."

Researchers haven't determined exactly why coronavirus causes this. It could be due to inflammation caused by the virus, or the virus binding to receptors in the nose that assist in the sense of smell.

Earlier studies have also found that losing the ability to detect scents is common with COVID-19. According to a study published in the Journal of the American Medical Association, 64% of coronavirus patients surveyed reported a loss of smell or taste, A July CDC survey found that the symptom lasted eight days on average, but some people experience it for weeks.

A long-term loss of smell or taste can be problematic, because it can discourage patients from eating, potentially causing malnutrition.

RELATED: 11 Symptoms of COVID You Never Want to Get

Other neurological symptoms also reported

Figuring out what's behind COVID anosmia might also help scientists unlock another mystery: Why long-term neurological symptoms often accompany coronavirus infection. An August study published in the Lancet a new study published in the Lancet found that 55% of people diagnosed with coronavirus had neurological symptoms three months after their diagnosis, including confusion, brain fog, personality changes, insomnia—and loss of taste and/or smell.

As for yourself, do everything you can to prevent getting—and spreading—COVID-19 in the first place: 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.