Morality rates
As of Feb 20, the crude fatality ratio of lab confirmed cases was around 3.8 percent. The overall fatality rates vary by location, and morality increases with age, with the highest being people over age 80.
The crude fatality ratio is higher among males compared to females (4.7% vs. 2.8%). And patients with underlying health conditions also had higher rates: 13.2% for those with cardiovascular disease, 9.2% for diabetes, 8.4% for hypertension, 8.0% for chronic respiratory disease, and 7.6% for cancer.
Because COVID-19 is a newly identified pathogen, there is no known pre-existing immunity in humans. Based on the epidemiologic characteristics observed so far in China, everyone is assumed to be susceptible.
There may be risk factors increasing susceptibility to infection. This requires further study, as well as to know whether there is neutralizing immunity after infection.