HealthDay News — Symptom order for COVID-19 may differ based on severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) variants, according to a study published online Dec. 16 in PLOS Computational Biology.

Joseph R. Larsen, from University of Southern California in Los Angeles, and colleagues developed a mathematical model predicting the order of symptoms based on data from the initial outbreak of SARS-CoV-2 in China using symptom occurrence at diagnosis. Modeling was used to assess the difference in symptom appearance between cases in the United States and China.

The researchers found that patients in China were more likely to have fever before cough and then nausea/vomiting before diarrhea, while U.S. patients were more likely to have cough before fever and then diarrhea before nausea/vomiting. The D614G SARS-CoV-2 variant that rapidly spread from Europe to predominate in the first U.S. wave of the outbreak was not present in the initial China outbreak and was hypothesized to affect symptom order. This hypothesis was supported using data from Japan that showed as SARS-CoV-2 shifted from the original Wuhan reference strain to the D614G variant, symptom order shifted to reflect the U.S. pattern.

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“These findings indicate that symptom order can change with mutation in viral disease and raise the possibility that D614G variant is more transmissible because infected people are more likely to cough in public before being incapacitated with fever,” the authors write.

One author disclosed financial ties to the pharmaceutical industry.

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