The Difference Between COVID-19 and the Flu Is This Order of Symptoms, Study Says

Flu season is upon us, and with coronavirus numbers rising in some states, many are growing concerned with being able to tell the difference between the two illnesses.

COVID-19 Versus the Flu

Symptoms for influenza and COVID-19 are unfortunately very similar, so it makes sense that folks are worrying that they won’t be able to tell what’s going on if they start feeling under the weather. Luckily, new research shows that when it comes to symptoms, there’s a specific order that tends to appear when someone has COVID-19 versus the flu.

In a new study, researchers out of the University of Southern California (USC) analyzed data from China and were able to determine that COVID-19 symptoms often appear in a certain order. Their hope is that this discovery will help people with COVID-19 get the treatment they need and self-isolate to stop the spread.

For their research, the team analyzed symptom data from the World Health Organization (WHO) for over 55,000 confirmed COVID-19 cases in China, as well as a set of data including about 1,100 COVID-19 cases collected between December 2019 and January 2020 which was provided by the National Health Commission of China.

To compare the order of COVID-19 symptoms to those of the flu, the researchers also analyzed data from over 2,400 reported cases of the flu in North America, Europe, and the Southern Hemisphere between 1994 and 1998. According to their results, the order of COVID-19 symptoms typically appears this way:

1. fever
2. cough and muscle pain
3. nausea or vomiting
4. diarrhea

In contrast, the researchers determined that the flu will most often begin with a dry cough that could later lead to other symptoms like fever, chills, and body aches.

“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 Peter Kuhn, PhD, one of the study authors. “Doctors can determine what steps to take to care for the patient, and they may prevent the patient’s condition from worsening.”

While these results may help guide healthcare providers and patients in distinguishing between the two conditions, it’s important to note that symptoms for COVID-19 can also differ from patient to patient.

Speaking to Healthline, Dr. Robert Glatter, emergency physician at Lenox Hill Hospital in New York, shared his personal experience treating COVID-19 patients during the peak of the outbreak. “In general, while fever is usually the most commonly described initial symptom of COVID-19 infection, the reality of what I see on the front lines is more variable,” he said. “In fact, some patients may present only with loss of taste or smell and otherwise feel well. I have also seen patients present with ‘COVID-toes,’ or chilblains; a livedo-type [reddish-blue discoloration] of skin reaction in response to acute inflammation, in the absence of fever, cough, or other respiratory symptoms.”

All this being said, as we head into what will surely be a challenging season, we will all need to pay close attention to any symptoms of illness we may experience, and the order in which they occur. If you notice you’ve suddenly come down with a fever or have lost your sense of smell or taste, contact your healthcare provider immediately and be sure to take extra measures with sanitizing and self-isolation. If we follow the guidelines provided by the CDC and other healthcare professionals, we are better equipped to make it through this tough time as best we can.