
You have a tickle in your throat, or cough a few times, maybe have a runny nose, and the thought crosses your mind: Is this COVID-19? While taking a test is the only way to be sure—a breakthrough infection, for example, may resemble a common cold, so get tested just in case—there are some telltale signs of COVID. One would be losing your sense of taste or smell, which happens to many, but not all, patients. The other would be a series of symptoms that appear in a particular order, according to a study from the University of Southern California. "This order is especially important to know when we have overlapping cycles of illnesses like the flu that coincide with infections of COVID-19," said Dr. Peter Kuhn, a USC professor of medicine, biomedical engineering, and aerospace and mechanical engineering. "Doctors can determine what steps to take to care for the patient, and they may prevent the patient's condition from worsening." Read on for the order they found—and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had COVID.
You May First Have a Fever

You can have COVID and not get a fever. In other words, you may get a headache, or shortness of breath or lose your sense of smell—and still have COVID with no fever. But you may get a fever. And if you do, it may be the first of a series of symptoms, say researchers at USC. A fever is defined as a temperature of more than 100.4 degrees Fahrenheit.
You May Then Have Cough and Muscle Pain

Dr. Anthony Fauci, the chief medical advisor to the President and the director of the National Institute of Allergy and Infectious Diseases, has warned of a "myalgia" or muscle pains when you get COVID—and it's a frequent symptom of Long COVID also. A dry cough—one that is unproductive—is also a common symptom.
You May Then Have Nausea or Vomiting

You may think of COVID as a respiratory illness, and this is only really affects your lungs. Wrong. COVID can affect all your body's systems, including your neurological system and your digestive system, resulting in gastrointestinal issues like nausea or vomiting.
You May Then Have Diarrhea

Last but not least in the order is this symptom. "Diarrhea caused by COVID-19 is similar to the upset tummy you might get from a regular stomach bug, such as rotavirus or norovirus," says the Zoe Symptom study. "We think COVID-19 causes diarrhea because the virus can invade cells in the gut and disrupt its normal function." Keep reading to learn about the other symptoms.
RELATED: COVID Myths Proven to Be False
Your Symptoms May Come in a Different Order—or Be Totally Different Overall

You may have migraines, heart palpitations, shortness of breath and none or all of the other symptoms you just read about. Some doctors say Delta symptoms are more likely to resemble a common cold. You may get a "headache, runny nose, sore throat," says Dr. Mary Ann Rogriguez of Baylor Scott & White. "And the thing is, young adults who are also the least likely to be vaccinated, may think they just have the usual common cold. I may still go out and party. They may just spread it."
What to Do if You Think You Have COVID

Get tested if you think you have COVID—a PCR test is considered the gold standard. Otherwise, stay home except to get medical care. "Most people with COVID-19 have mild illness and can recover at home without medical care. Do not leave your home, except to get medical care. Do not visit public areas," says the CDC. "Take care of yourself. Get rest and stay hydrated. Take over-the-counter medicines, such as acetaminophen, to help you feel better." And to protect your life and the lives of others, don't visit any of these 35 Places You're Most Likely to Catch COVID.