The incubation period (time from exposure to the development of symptoms) of the virus is estimated to be between 2 and 14 days based on the following sources:
The estimated range will be most likely narrowed down as more data becomes available.
The incubation period has been found to be as long as 24 days (range: 0-24 days; median: 3.0 days) in a study by Zhong Nan-Shan published on February 9. The study has yet to be peer reviewed.
The WHO said in a press conference on February 10 that:
A Chinese study published in the New England Journal of Medicine on Jan. 30, has found the incubation period to be 5.2 days on average, but it varies greatly among patients. The Chinese team conducting the study said their findings support a 14-day medical observation period for people exposed to the pathogen.
Below is an extract of the study findings (highlight added by Worldometer):
Early Transmission Dynamics in Wuhan, China, of Novel Coronavirus–Infected Pneumonia - Qun Li et al., New England Journal of Medicine, Jan. 29, 2020
Among the first 425 patients with confirmed NCIP, the median age was 59 years and 56% were male. The majority of cases (55%) with onset before January 1, 2020, were linked to the Huanan Seafood Wholesale Market, as compared with 8.6% of the subsequent cases.
The mean incubation period was 5.2 days (95% confidence interval [CI], 4.1 to 7.0), with the 95th percentile of the distribution at 12.5 days.
In its early stages, the epidemic doubled in size every 7.4 days. With a mean serial interval of 7.5 days (95% CI, 5.3 to 19), the basic reproductive number was estimated to be 2.2 (95% CI, 1.4 to 3.9).
Conclusions On the basis of this information, there is evidence that human-to-human transmission has occurred among close contacts since the middle of December 2019. Considerable efforts to reduce transmission will be required to control outbreaks if similar dynamics apply elsewhere. Measures to prevent or reduce transmission should be implemented in populations at risk.
A study financed by the Netherlands Ministry of Health and published on Eurosurveillance, analyzed data on 88 cases with known travel history (to and) from Wuhan which were detected between 20 and 28 January as being infected with 2019-nCoV.
The mean incubation period was estimated to be 6.4 days. The incubation period ranges from 2.1 to 11.1 days. The upper limit of 11.1 days could be considered conservative.
Understanding the incubation period is very important for health authorities as it allows them to introduce more effective quarantine systems for people suspected of carrying the virus, as a way of controlling and hopefully preventing the spread of the virus.
For comparison, the incubation period for the common flu (seasonal influenza) is typically around 2 days. Incubation period for other coronaviruses: SARS 2-7 days; MERS 5 days typically (range 2-14 days).
|Virus||Incubation Period |
|2-14 or 0-24 days *|
|2-7 days, |
as long as 10 days
|5 days (range: 2-14)|
|1-4 days, |
as long as 7 days
|2 days (1-4 range)|