The most likely order of symptoms that COVID-19 patients experience is different for different variants of the virus, according to a new study published in PLOS Computational Biology by Peter Kuhn of the University of Southern California and colleagues.
The researchers previously developed a mathematical model that predicts the order of COVID-19 symptoms based on data from the initial outbreak in China in early 2020. In the new work, they wanted to know if the order of symptoms varied in patients from different regions. geographical or with various characteristics of the patient. They used their modeling approach to predict the order of symptoms in a set of 373,883 cases in the US between January and May 2020.
Surprisingly, the most likely order of symptoms differed between the initial outbreak in China, where fever most frequently preceded cough and nausea/vomiting was a third common symptom, and the subsequent spread to the US, where the cough was more likely to be the first symptom. and diarrhea was a third most common symptom.
By analyzing additional data from Brazil, Hong Kong and Japan, the team showed that the different orders of symptoms were not associated with geographic region, climate or patient characteristics, but with SARS-CoV-2 variants .
The presence of the D614G variant in an area, which was predominant in the US in early 2020, was associated with a higher likelihood of cough being the first COVID-19 symptom experienced by patients. As Japan moved from the original Wuhan reference strain to the D614G variant, the order of symptoms also changed.
Fever was the most likely first symptom in early COVID-19 cases, while cough is the most likely first symptom in more recent cases of the D614G variant.
“These findings indicate that the order of symptoms may change with the mutation in the viral disease and raise the possibility that the D614G variant is more transmissible because infected people are more likely to cough in public before becoming incapacitated with fever,” they say.
