Why is quarantine only 14 days? Have there been cases when the coronavirus manifested itself after 20, 30, 40 days?
According to most estimates, the duration of the incubation period (the time between infection and the onset of clinical symptoms of the disease) COVID-19 ranges from 1 to 14 days and most often is about five days.
A study by a group of scientists from the Johns Hopkins Bloomberg School of Public Health at the Johns Hopkins University, led by Professor Justin Lessler, a professor in the Department of Epidemiology, was published on March 10, 2020 in the journal Annals of internal medicine and is freely available.
To evaluate the incubation period of COVID-19, 181 confirmed cases of virus infection were studied. It turned out that in 97.5% of patients, the first symptoms of coronavirus infection manifested themselves after 11.5 days (diagnostic interval (CI) from 8.2 to 15.6 days) after the estimated time of infection. In 2.5%, signs of the disease appeared within two days. The average incubation period was 5.1 days (95% of the diagnostic interval (CI) from 4.5 to 5.8 days). The obtained results confirm the proposal regarding the duration of quarantine for 14 days, although in extreme cases a longer incubation period is possible, i.e., symptoms of the disease may occur after 14 days of quarantine.
Thus, two-week quarantine for alleged carriers of the virus is an effective method of combating the spread of the disease, the researchers note. At the same time, they acknowledge that in about 1% of cases, symptoms appear after a 14-day period.