Epidemiologic Analysis of Wuhan Coronavirus Demonstrates Up To Two-Week-Long Incubation Period and One-Week Doubling Time

Researchers affiliated with the Chinese Centers for Disease Control and Prevention recently analyzed the first 425 confirmed cases of the Wuhan coronavirus to better understand epidemiologic characteristics of the disease.

Patients with laboratory-confirmed infection by the virus in December 2019 and January 2020 were surveyed for demographic characteristics, exposure timeline, and disease course. While cases prior to January 1st, 2020 were primarily (55%) affiliated with the Huanan Seafood Wholesale Market, later cases were found to be associated with the human-to-human spread of the virus, which had a mean incubation period of 5.2 days.

However, the researchers found that the incubation period could extend up to and beyond 12.5 days, indicating that some patients infected by the virus do not demonstrate symptoms until nearly two weeks after contracting the disease. In these beginning stages of the epidemic, the doubling size was calculated to be 7.4 days.

The researchers concluded that human-to-human transmission of the virus has occurred since mid-December 2019 and recommended the implementation of preventative measures in at-risk populations. The study was funded, among others, by the Ministry of Science and Technology of China.

Li Q, Guan X, Wu P, et al. (2020) Early Transmission Dynamics in Wuhan, China, of Novel Coronavirus–Infected Pneumonia. The New England Journal of Medicine.