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Study: 13% to 18% of COVID-19 cases are symptomatic

A new study suggests that 13% to 18% of COVID-19 patients had symptoms

Motorists line up a COVID-19 vaccination site at California State University Northridge Monday, Feb. 8, 2021, in Northridge, Calif.
Motorists line up a COVID-19 vaccination site at California State University Northridge Monday, Feb. 8, 2021, in Northridge, Calif. A new study suggests that as little as 13% to 18% of COVID-19 cases are symptomatic.
Marcio Jose Sanchez, Associated Press

A new study suggests that as little as 13% to 18% of COVID-19 cases are symptomatic, Business Insider reports.

What happened?

Researchers at the University of Chicago created a new model that looked at antibody tests in New York from March to April 2020, COVID-19 cases data for the city from March to June and reviewed testing capacity changes in New York from that time span as well.

  • The study found, in all, 13% to 18% of COVID-19 cases included patients who showed COVID-19 symptoms.
  • If those numbers are accurate, it would mean that 80% of COVID-19 cases are asymptomatic.
  • “There are a lot of asymptomatic people — much larger than many studies have assumed,” Rahul Subramanian, one of the study’s authors, told Insider.

Key quote

  • “Even if asymptomatic people aren’t transmitting the virus at high rates, they constitute something like 80% of all infections,” said study co-author Qixin He, assistant professor at Purdue University. “This proportion is quite surprising. It’s crucial that everyone — including individuals who don’t show symptoms — adhere to public health guidelines, such as mask wearing and social distancing, and that mass testing is made easily accessible to all.”

More data

Back in November, the Centers for Disease Control and Prevention said people without symptoms are responsible for much of the spread of the novel coronavirus, as I wrote for the Deseret News. Asymptomatic patients are unaware they’re carrying the virus, which has led to the spread.

  • “Most SARS-CoV-2 infections are spread by people without symptoms.”
  • “CDC and others estimate that more than 50% of all infections are transmitted from people who are not exhibiting symptoms.”
  • “This means at least half of new infections come from people likely unaware they are infectious to others.”

The CDC said masks are the key, then, to curbing the spread.