7 Hidden Symptoms of COVID Have Been Found

For doctors and health officials, one of the most confounding things about coronavirus is that many people who are infected don't show symptoms, seriously hampering efforts at containing the disease. Just how many? According to a new study published in PLOS Medicine, 1 in 5 people with COVID-19 don't have symptoms of the virus but are still contagious. And other symptoms may be "hidden" — vague maladies that can easily be confused for something else or dismissed as minor. Here are seven hidden symptoms of COVID. Read on, and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had Coronavirus.

Vomiting and diarrhea are common symptoms of food poisoning, stomach flu—and COVID-19. Research from Wuhan, China, found that 50% of coronavirus patients reported gastrointestinal symptoms such as diarrhea, vomiting or stomachache. Like the other hidden symptoms on this list, GI problems may be the only symptom of COVID you have.

"COVID toes" may be one of the weirdest phenomena associated with coronavirus infection. Or maybe not: Up to 20% of people with COVID-19 report skin changes, such as a red, bumpy rash; hives; or breakouts resembling chicken pox. These are so common that scientists undertaking the COVID Symptom Study, say skin rashes should be named a fourth key sign of COVID-19, alongside fever, cough and loss of smell or taste.

Many people with COVID report experiencing confusion or the ability to concentrate, a.k.a. "brain fog," which can linger. In August, a study published in the Lancet found than 55% of people diagnosed with coronavirus have neurological symptoms three months after their diagnosis.

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Like many viruses, COVID can really make you feel run down, even if you don't experience more hallmark symptoms of the disease. Post-COVID fatigue can last for weeks or months. "We're starting to see more and more people who apparently recover from the actual viral part of it, and then weeks later, they feel weak, they feel tired, they feel sluggish, they feel short of breath," said Dr. Anthony Fauci, the nation's top infectious-disease expert. "It's very disturbing, because if this is true for a lot of people, then just recovering from this may not be okay. You may have weeks where you feel not exactly correct."

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In some people, coronavirus seems to cause eye symptoms, including dry, red, or itchy eyes, conjunctivitis (a.k.a. pink eye), enlarged blood vessels, swollen eyelids, excessive watering and increased discharge. And it's quite common: According to a study in JAMA Ophthalmology, nearly one-third of hospitalized COVID-19 patients reported eye issues.

That cough that comes and goes—is it allergies or COVID? Runny nose, dry cough and congestion are easy to write off as seasonal allergies, especially if you're feeling otherwise well. But they're also three of the hallmark signs of COVID-19.

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The coronavirus can attack the inner ear, causing dizziness, vertigo, tinnitus (ringing in the ears), fainting—even hearing problems. "Researchers are looking into a possible connection between COVID-19 and hearing loss," AARP reported. "Often these issues persist even after other symptoms of the illness subside."

So 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.