A person wearing a protective mask sits in a Bay Area Rapid Transit (BART) train car in San Francisco, California, on Wednesday, Feb. 26, 2020.
David Paul Morris | Bloomberg | Getty Images
It takes an average of about five days for COVID-19 symptoms to show after contracting the virus, while the vast majority of people infected will develop symptoms within 12 days, researchers confirmed in a new report published Monday in the journal Annals of Internal Medicine.
The American College of Physicians said 97.5% of people infected with the new coronavirus will show symptoms within 12 days of catching the virus. The average incubation time is five days, researchers said. That’s in line with current Centers for Disease Control and Prevention recommendations that call for patients to remain in quarantine or self-isolation for 14 days after potential exposure.
Researchers from Johns Hopkins Bloomberg School of Public Health analyzed reports from 50 provinces, regions and countries outside of Wuhan, China, to determine the virus’s incubation period. Researchers found 181 confirmed cases with time frames for identifiable exposure and symptom onset.
“Based on the available data, the researchers estimated the median incubation period of COVID-19 to be 5.1 days and 97.5 percent of those who develop symptoms appeared to do so within 11.5 days of infection. These estimates imply that, under conservative assumptions, 101 out of every 10,000 cases will develop symptoms after 14 days of active monitoring or quarantine, which supports current CDC recommendations,” researchers wrote in a press release.
The seasonal flu, which has infected 34 million people in the U.S. so far this season, has an incubation period of one to four days.
The two viruses have similar symptoms, which some health officials fear will cause misdiagnoses. Common flu symptoms include fever, cough, sore throat and aches. COVID-19 symptoms include fever, cough and shortness of breath, according to the CDC.
Though the virus is thought to mainly spread from person to person through close contact and respiratory droplets. It’s also possible that people can spread the virus without showing symptoms.