contact tracing

noun

process of finding and identifying people in close contact with someone who is infected with a transmissible pathogen

The process of identification of persons ("contacts") who may have come into contact with a person carrying an infectious disease.
“There's a strong case for replacing the present system of anonymous testing with mandatory reporting of new infections, and vigorous contact tracing of sexual and needle-sharing partners.”
“Other health care professionals also may be trained as part of the effort to more than double to 1,500 the number of people conducting interviews and contact tracings on an ongoing basis.”