People with coronavirus symptoms may only experience them five days after their exposure to the virus, according to a study published in the journal Annals of Internal Medicine.
The study “The Incubation Period of Coronavirus Disease 2019 (COVID-19) From Publicly Reported Confirmed Cases: Estimation and Application” discovered that people would manifest coronavirus symptoms 5.1 days after their initial exposure. It was the median length as incubation periods vary. Some people show signs of illness within two weeks.
“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 Justin Lessler of the Johns Hopkins Bloomberg School of Public Health and senior author of the report.
The results did not touch on the extent to which people can spread the virus during the symptom-free period. However, preliminary evidence reveals there is a short window before infected individuals feel ill when they can transmit the virus to others.
Lessler’s team reported that for 98% of people who acquire symptoms of COVID-19, the transmission of the virus can take place within 11.5 days of exposure. The researchers suggest that for every 10,000 individuals quarantined for 14 days, only 101 would manifest symptoms upon release from quarantine.
The data gathered by Lessler and colleagues was based on 181 cases from China and other countries that were identified before 24 February. These cases involved travel to or from Wuhan, China, or contact with other people who had been there.
Findings show that coronaviruses that trigger common colds usually have a three-day symptom-free period after infection.
Graham Cooke, professor of infectious diseases at Imperial College London, pointed out that people must not treat the findings as a clear bill of health if no signs of illness show up within five days of a potential exposure. “That’s absolutely the wrong interpretation,” he said. “At five days, half of people won’t yet have developed symptoms.”
