How the coronavirus came to Germany

The transcript details the case of Germany's Patient Zero, a Chinese woman from Shanghai who traveled to Germany for meetings. Her parents visited her from Wuhan before her trip. Doctors traced the virus spread by examining meeting records and interviewing employees. The first German infected sat next to her on January 20th. Case 4, infected on January 22nd, had regular contact with her and shared a salt shaker with a coworker, who became the fifth infected person.

On what date did the first German person get infected?

How did the fifth person become infected?