Winter Is Coming: How to Differentiate Between Flu and COVID-19?

COVID-19 symptoms are numerous, and over recent months, more symptoms have been added to the common list. Now, researchers from the University of Southern California have organized these symptoms and identified the order in which an individual infected with the virus is likely to experience them. The aim of the study is to assist doctors in identifying COVID-19 patients at an earlier stage to provide the appropriate treatment. Additionally, this identification is particularly important with winter approaching, as winter brings other illnesses like the flu, necessitating an efficient method to at least initially distinguish between COVID-19 and other diseases.

The study focused on symptoms that are easily identifiable and can be recognized objectively—unlike neurological symptoms or symptoms like loss of taste and smell, which are harder to objectively identify. According to the study, the typical order of prominent COVID-19 symptoms is fever first, followed by the development of a cough, then nausea and/or vomiting, and finally diarrhea. This order is, of course, just the most typical order, and in some patients, the sequence might vary—but familiarity with the common order can facilitate the recognition of the disease. The least likely sequence of COVID-19 symptoms is the exact opposite order: diarrhea, nausea and vomiting, cough, and finally fever.

Professor Peter Kuhn issued a public statement following this research, asserting that awareness of this order is particularly important when there are overlapping cycles of other illnesses like the flu, whose symptoms correspond to COVID-19 infections.

As mentioned, this order is not absolute, but since it is the most common, the team from the University of California, who conducted the research, strongly supports the idea of taking temperatures when entering public buildings as an effective preventive measure against infection. Until a vaccine or cure for COVID-19 is found, the team hopes that awareness of the symptom sequence will save lives through early detection of infection.

Simultaneously, they argue that the research accuracy could have been higher if doctors consistently documented patients' symptoms chronologically—something that, for some reason, is not routinely done. If such precise documentation were available, it would be easier to gather accurate data and draw more precise conclusions. Nevertheless, this symptom sequence does appear to be the most common and should be used to identify COVID-19 infections.