Order of symptoms may help distinguish COVID-19 from the flu
It has been over nine months since the coronavirus pandemic first hit and the outbreak shows little signs of ending. Now, with the onset of the flu season, many have been left worried since the two diseases have frustratingly similar symptoms—fever, coughing, nausea, etc. These are also symptoms witnessed in a host of other diseases. So, how could you tell if you have COVID-19?
A modeling study published in the Frontiers in Public Health journal in August might help understand how one could differentiate between COVID-19 and other diseases. The study looked at data from infections of the novel coronavirus SARS-CoV-2 (that causes COVID-19) against other respiratory diseases, such as influenza, SARS (Severe Acute Respiratory Syndrome), and MERS (Middle East Respiratory Syndrome).
The study examined a dataset of the World Health Organization, containing 55,924 confirmed COVID-19 cases from China between February 16 to 24, 2020. The study expanded its analysis with 1,099 cases that were collected by the China Medical Treatment Expert Group via the National Health Commission of China between December 11, 2019, to January 29, 2020.
Further, the team examined a dataset from 2,470 confirmed influenza cases of mostly unvaccinated patients in Europe, North America, and the Southern Hemisphere reported to health authorities from 1994-1998. The datasets representing symptom frequency in MERS, containing 245 patients, and SARS, containing 357 patients, were collected on admission and were reported as clinical data from two physicians—one based in Beijing and another in Chicago.
The study found that COVID-19 symptoms likely appeared in the order: fever, cough, nausea/vomiting, and diarrhea. The study noted that influenza is distinct from the other three diseases as it initiates with a cough. COVID-19, SARS, and MERS start with a fever, it said. Among these three, COVID-19 may be differentiated on the basis of symptoms in the upper and lower gastrointestinal tract.
"The first two symptoms of COVID-19, SARS, and MERS are fever and cough. The upper GI tract (i.e., nausea/vomiting) seems to be affected before the lower GI tract (i.e., diarrhea) in COVID-19, which is the opposite from MERS and SARS," the researchers wrote.
Author Peter Kuhn—Professor of Biological Sciences and Professor of Medicine, Biomedical Engineering, and Aerospace & Mechanical Engineering at USC Dornsife—noted, "This order is especially important to know when we have overlapping cycles of illnesses like the flu that coincide with infections of COVID-19." "Doctors can determine what steps to take to care for the patient, and they may prevent the patient's condition from worsening."
Based on the study, the researchers recommend that fever should be used to screen for entry into facilities as regions begin to reopen. "Additionally, our findings suggest that good clinical practice should involve recording the order of symptom occurrence in COVID-19 and other diseases," the researchers wrote, suggesting that this may prevent local outbreaks from evolving into pandemics.
Meanwhile, speaking to Healthline, Dr. Robert Glatter—emergency physician, Lenox Hill Hospital, in New York—said that while the study's findings are useful, symptoms on the frontlines are variable. Dr. Glatter said some patients may only exhibit a loss of smell/taste, while others present with 'COVID-toes' (chilblains). Dr. Glatter also warned that people may contract both influenza and COVID-19, suggesting the possibility of a "twindemic."
