Researchers at the University of Southern California have found that COVID-19 symptoms often manifest in patients in a particular order. According to a scientific paper entitled ‘Modeling the Onset of COVID-19 Symptoms’, published in the Frontiers in Public Health journal, the team attempted to discern the most common order in which symptoms presented themselves. The intention was to enable healthcare professionals to more quickly distinguish cases of COVID-19 from other conditions with similar symptoms, such as flu and allergies.
Using World Health Organization data from more than 55,000 patients in China, the research team determined that fever is most frequently the first symptom of the virus. This is followed by a cough, then aches and pains in the throat, muscles, and head, then nausea and/or vomiting. Diarrhea is the last symptom to appear.
“Our model predicts that influenza initiates with cough, whereas COVID-19 like other coronavirus-related diseases initiates with fever,” the study reads. “However, COVID-19 differs from SARS and MERS in the order of gastrointestinal symptoms. Our results support the notion that fever should be used to screen for entry into facilities as regions begin to reopen after the outbreak of Spring 2020.”
While these findings may be useful in helping frontline healthcare workers distinguish new cases of coronavirus from the common cold of flu, other experts have pointed out that this order of symptoms will not be the same for each patient. Another potential flaw that has been flagged by critics of the study is the issue of recall bias; namely, patients struggling to accurately remember which of their symptoms they experienced first.
“It’s not going to be universal,” said Dr. William Schaffner, a specialist in infectious diseases at Vanderbilt University’s School of Medicine. “We know, for starters, that a number of people don’t have a fever.”
This study may provide some insight into the way in which COVID-19 symptoms present themselves in patients, but the consensus among the scientific community seems to lean towards the idea that equally close attention should be paid to other symptoms including shortness of breath, loss of taste or smell, and fatigue.