A study led by experts at the University of Southern California, Los Angeles, United States has shown the most likely order of discerning COVID-19 symptoms.
The study, published in the journal Frontiers in Public Health, suggests that the order of symptom occurrence could help patients and medical professionals to more quickly distinguish COVID-19 from other respiratory diseases.
“Additionally, our findings suggest that good clinical practice should involve recording the order of symptom occurrence in COVID-19 and other diseases.
“If such a systemic clinical practice had been standard since ancient diseases, perhaps the transition from local outbreak to pandemic could have been avoided,” the authors say.
To compare the order of COVID-19 symptoms to influenza, the researchers examined data from 2,470 cases in North America, Europe, and the Southern Hemisphere that was reported to health authorities from 1994 to 1998.
The order of symptom occurrence in COVID-19 according to the experts are fever, cough, nausea/vomiting, and diarrhoea.
1. COVID-19 initiates with fever: The authors say their model predicts that influenza initiates with cough, whereas COVID-19 like other coronavirus-related diseases initiates with fever.
“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,” they say.
2. Cough: The experts say the most likely next symptom of COVID-19 after the fever is cough.
“The likelihoods of transitioning to fever, 0.769, and then to cough, 0.958, are high, and these observations indicate that a large portion of infected symptomatic patients may follow this path,” they noted.
They say their results suggest that in patients with SARS-CoV-2, the body first develops a fever, then upper respiratory symptoms, and finally symptoms of the upper then lower gastrointestinal tract.
According to the World Health Organisation, the most common symptoms of COVID-19 are fever, dry cough, and tiredness.
“Other symptoms that are less common and may affect some patients include loss of taste or smell, aches, and pains, headache, sore throat, nasal congestion, red eyes, diarrhoea, or a skin rash,” the world health body said.
3. Nausea/Vomiting: The researchers found that in addition to upper respiratory symptoms, COVID-19 patients suffer from nausea and vomiting.
According to them, these observations are consistent with the symptoms described by theCenter for Disease Control and Prevention in the USA and support the notion that fever followed by cough seems highly likely to be diagnosed as COVID-19.
4. Finally, diarrhoea: The authors say a person infected with COVID-19 is most likely to experience symptoms in the order of fever, cough, nausea/vomiting, then diarrhoea.
“Finally, this implementation of the model predicts that nausea/vomiting occurs before diarrhea. These two results suggest that in patients with SARS-CoV-2, the body first develops a fever, then upper respiratory symptoms, and finally symptoms of the upper then lower gastrointestinal tract.
“To further investigate these symptom paths, we implemented the Stochastic Progression Model with the main dataset (COVID-19 with N = 55,924), to determine the likely downstream paths when the first one or two symptoms are forced to a certain state. The gray lines represent the ‘forced’ paths.
“The rest of the paths were determined as before with a greedy algorithmic approach. We found that the most likely orders of the downstream path are consistent with the most likely orders of the unforced paths. Even if the first symptom is forced to be an unlikely one (e.g., diarrhea), the downstream paths maintain the most likely order of the other three symptoms that we originally determined.
“Similarly, the GI tract effects occur first in the forced least likely paths. When forcing the path one step further by predetermining the first two symptoms for both the most and least likely paths, the findings remain the same,” they say.
The experts say the importance of knowing the first symptoms is rooted in the need to stop the spread of COVID-19, a disease that is two to three times more transmissible than influenza and results in outbreaks of clusters.
“There is a heightened risk in COVID-19 being passed on, so faster testing and social distancing are important, especially when social distancing and quarantine measures are relaxed.
“Our results assert that fever is the most likely symptom to occur first in symptomatic adult patients with COVID-19. We hope that the hypotheses generated in this work are tested with prospective clinical data to confirm that a cough occurs first more often in influenza and likewise fever in COVID-19,” they noted.
Reacting to the study, a Consultant Family Physician at the Lagos State University Teaching Hospital, Ikeja, Dr. Olujimi Sodipo, said one cannot specifically highlight the symptoms of COVID-19.
“What has been seen from various studies is that you have different variants of the coronavirus and there has also been a typical presentation of people presenting in ways that will not even make people think that it is COVID-19.
“But of course, there are some common symptoms that are seen with COVID-19 and that is why in some of the publications, they try to highlight some of the common symptoms but the absence of those common symptoms do not mean that one doesn’t have COVID-19.
“So, from the case definition, things like fever, cough, difficulty in breathing are common symptoms seen in COVID-19.
“They’ve also seen that some other symptoms coming up now are anosmia. When you see someone with that symptom, you have to suspect COVID-19. But you don’t need to have those symptoms but one of the common things in people that have severe ones is that a number of them have difficulty in breathing and reduction in oxygen level,” Sodipo said.
He, however, advised that people who are being tested for COVID-19 should monitor their oxygen levels.
According to him, the oxygen level may be dropping without knowing.
“One common symptom is extreme fatigue and because that is what is seen in malaria; and people think it’s malaria. So, what we are seeing, especially for the elderly and the ones with co-morbidity is that they should be monitoring their oxygen level,” Sodipo noted.
Meanwhile, the Lagos State Commissioner for Health, Prof. Akin Abayomi highlights the common symptoms of COVID-19 in the state as cough, fever, shortness of breath, general weakness, chest pain, anosmia, loss of appetite.
Other symptoms include body pain, loss of taste, catarrh, nausea, running nose, chills, and erectile dysfunction.
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