a person whose job is to find any other people that an infected person has met or had close contact with, usually in order to control the spread of an infectious disease

Thousands of new contact tracers were enlisted to communicate with people who test positive for coronavirus. 新近征召了几千名接触者追踪员，任务是与新冠病毒测试阳性的人沟通。

You are required to inform the contact tracer of the names of anyone else living at your address. 你被要求向接触者追踪员报告所有和你住在同一地址的人的姓名。