What is viral shedding?

People who are infected with COVID-19 might be spreading the virus without even knowing it due to viral shedding.

The coronavirus continues to spread throughout the United States, and a lot of the transmission can be tied to the act of “viral shedding.”

What is viral shedding?

Viral shedding is basically any way that the virus spreads from one person to another.

The Mayo Clinic defines viral shedding as: “When a person is infected with a virus, the virus multiplies in the body and can be released into the environment through sneezing, coughing or even speaking. This release is called ‘shedding’ and viral shedding is how COVID-19 is spread from person to person.”

Why is it different with COVID-19?

Here’s some perspective. Viral shedding for two other common coronaviruses — like SARS and Middle East Respiratory Syndrome — don’t start until a week or longer after symptoms begin, according to a new study from researchers at the University of St. Andrews in Scotland

  • This allows people who have the virus to quarantine and stay as far away as possible from others without passing it on.

COVID-19, though, doesn’t work the same way. Some patients never experience symptoms. Others shed the virus before symptoms start to arrive, which makes it easier to pass on the virus without even knowing you had it, the researchers said.

This woman spread coronavirus for at least 70 days without knowing she had it
Study: Coronavirus could live in patients for five weeks

How long does it last with COVID-19?

  • Officials remain unclear how long infected patients spread the novel coronavirus. One woman reportedly shed the virus for 70 days after her infection.
  • The CDC has looked at some data and said “persons with mild to moderate COVID-19 remain infectious no longer than 10 days after symptom onset. Persons with more severe to critical illness or severe immunocompromise likely remain infectious no longer than 20 days after symptom onset.”
University of Utah researchers studying hydroxychloroquine to stem COVID-19 spread

Why understanding viral shedding is important

Getting a clear answer on how viral shedding works for COVID-19 can make a difference in determining how long people should quarantine, what types of environments people should avoid and how to keep everyone safe.

Senior author Vincent Munster, a virologist at the National Institute of Allergy and Infectious Diseases, said recently that it’s important to know how people share the virus, as I wrote about for the Deseret News.

  • “At the time we started this study, we really didn’t know much about the duration of virus shedding,” he said. “As this virus continues to spread, more people with a range of immunosuppressing disorders will become infected, and it’s important to understand how SARS-CoV-2 behaves in these populations.”
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