COVID-19 and CLINICAL FEATURES

Incubation period — The incubation period for COVID-19 is thought to be within 14 days following exposure, with most cases occurring approximately four to five days after exposure.

A study with 1099 patients with confirmed symptomatic COVID-19, the median incubation period was four days (interquartile range two to seven days).

Using data from 181 publicly reported, confirmed cases from China with identifiable exposure, one modeling study estimated that symptoms would develop in 2.5 percent of infected individuals within 2.2 days and in 97.5 percent of infected individuals within 11.5 days. The median incubation period in this study was 5.1 days.

Spectrum of illness severity (COVID-19)

The spectrum of symptomatic infection ranges from mild to critical; most infections are not severe. Specifically, in a report from the Chinese Center for Disease Control and Prevention that included approximately 44,500 confirmed infections with an estimation of disease severity:

●Mild (no or mild pneumonia) was reported in 81 percent.

●Severe disease (eg, with dyspnea, hypoxia, or >50 percent lung involvement on imaging within 24 to 48 hours) was reported in 14 percent.

●Critical disease (eg, with respiratory failure, shock, or multiorgan dysfunction) was reported in 5 percent.

●The overall case fatality rate was 2.3 percent; no deaths were reported among noncritical cases.


According to a joint World Health Organization (WHO)-China fact-finding mission, the case-fatality rate ranged from 5.8 percent in Wuhan to 0.7 percent in the rest of China. Most of the fatal cases occurred in patients with advanced age or underlying medical comorbidities.