Cough, Cough – Researchers May Have Discovered Why First COVID-19 Wave Spread So Fast in US and Europe

COVID-19 may have spread faster in the US because the first symptom was a cough.

Research by USC researchers shows that the order of symptoms in the first wave of COVID-19 varied between virus strains.

The strain of the COVID-19 virus that circulated in the United States and Europe during the first wave of the pandemic may have been particularly contagious because the most common first symptom was likely to be a cough, according to a study led by researchers at USC Dornsife. College of Letters, Arts and Sciences.

The study suggests that people infected with what was the world’s most contagious strain of COVID-19 in May 2020, and the most dominant strain in the US two months later, would likely develop a cough as their first symptom, followed by a fever. The research was conducted at the USC Michelson Center for Convergent Bioscience at the Convergent Science Institute in Cancer under the direction of Peter Kuhn.

The greater transmissibility of that variant – D614G – can be explained by infected individuals coughing and spreading the virus before being incapacitated by a fever. COVID-19 is usually spread through respiratory droplets, often aggravated by a cough from symptomatic patients.

Conversely, those infected with the COVID-19 variant, the Wuhan reference strain, during the first outbreak in China have likely experienced a fever as their first symptom, followed by a cough.

Studying the likely order of symptoms, in addition to how the disease spreads, can inform additional research and health care about how people experience the disease.

The study, published today (Dec. 16, 2021) by PLOS Computational Biology, also noted that:

In Japan, fever was probably the first symptom when the Wuhan reference strain was dominant there. When the D614G variant supplanted it, coughing was probably the first symptom. This finding validates similar results from other geographic regions and supports the hypothesis that cough occurs earlier in the D614G variant than the Wuhan reference strain. The predicted symptom order was not altered by region, weather, patient age, or co-morbidity. The study did not answer the question of whether the order of symptoms found in the first waves of the pandemic also applies to current variants.

Expert analysis

“With the emergence of new variants and the likelihood of COVID-19 becoming endemic in the population, it is important that researchers continue to demonstrate how viral variants influence the progression of symptoms and disease in individuals and populations.”

Peter Kuhn, a dean professor of biological sciences and professor of biological sciences, medicine, biomedical engineering, and aerospace and mechanical engineering.

“Studying the likely sequence of symptoms may increase our understanding of how disease spreads and further inform future research and health care about how individuals are likely to experience disease.”

Joseph Larsen, graduate researcher at USC’s Convergent Science Institute of Cancer and PhD candidate in USC Dornsife’s Division of Quantitative and Computational Biology.

Background

The latest findings complement research published in August 2020 by Kuhn and his collaborators that discovered the sequence of symptoms of the Wuhan reference strain. The discovery was based on a mathematical model using data from an outbreak in China in early 2020.

Reference: “Modeling the onset of symptoms of COVID-19: effects of SARS-CoV-2 variant” Dec 16, 2021, PLoS Computational Biology.
DOI: 10.1371/journal.pcbi.1009629

About the study

In addition to Kuhn and Larsen, the co-authors of the USC Dornsife study were James B. Hicks, professor of (research) in biological sciences. Kuhn, Hicks and Larsen are also affiliated with the USC Michelson Center for Convergent Bioscience. Other authors included Margaret Martin of the Department of Computer Science at Tufts University and John Martin of Materia Therapeutics.

Funding support came from the Hsieh Family Foundation and the Kathy & Richard Leventhal Research Fund. Larsen also received support from USC Dornsife and the Schlegel Family Endowment Fellowship.

About USC Dornsife

The USC Dornsife College of Letters, Arts and Sciences is the oldest school at the University of Southern California and works in the natural sciences, social sciences, and humanities, exploring fundamental questions about who we are, how the world works, and what we can do to help society. improve and enrich.

About the USC Michelson Center

The USC Michelson Center for Convergent Bioscience was established to accelerate discovery from the couch to the bedside. The physical hub of this effort is Michelson Hall, a state-of-the-art research building with advanced technology platforms and the core of several research programs. The Michelson Center includes researchers from USC Dornsife, the USC Viterbi School of Engineering, USC’s Keck School of Medicine, as well as the USC School of Cinematic Arts and the Information Sciences Institute.