A new study by researchers at Johns Hopkins Bloomberg School of Public Health finds that the median incubation period of the respiratory illness COVID-19 is 5.1 days.
14-Day Quarantine Period Reasonable
The researchers analyzed publicly available data on infections by the coronavirus SARS-CoV-2 which caused COVID-19. Based on this incubation period, the researchers said the 14-day quarantine period used by the U.S. Centers for Disease Control and Prevention for individuals with likely exposure to the coronavirus is reasonable.
The study was published online on March 9 in the journal Annals of Internal Medicine.
Also based on the study data, about 97.5 percent of people who develop symptoms after infection will do so within 11.5 days of exposure. The data also showed only 101 out of 10,000 individuals who were quarantined for the 14-day period would develop symptoms after being released from quarantine.
Cases Published in the Media
The data the researchers analyzed were published in the media, consisting of 181 cases from China and other countries. The cases were detected before February 24, 2020. The cases all had likely dates of exposure and symptom onset. Most of the cases were from individuals who traveled through the city of Wuhan, China (the epicenter of the epidemic), or from individuals exposed to the virus in Hubei Province (Wuhan is the capital of the province).
Most health authorities around the world have been using the 14-day quarantine period for individuals who have traveled in heavily infected regions, or who have come into contact with infected individuals.
“Based on our analysis of publicly available data, the current recommendation of 14 days for active monitoring or quarantine is reasonable, although with that period some cases would be missed over the long-term,” said senior author of the study, Justin Lessler.
The coronavirus SARS-CoV-2 that originated in Wuhan, China has now spread to over 100 countries and have killed thousands.