TABLE 1.

Factors Associated With the Need to Implement In-Depth Case Investigation, Contact Tracing, and Case Management*

	Factors Associated With the Need for in-Depth Case Investigation	Factors Associated With the Need to Implement Contact Tracing	Factors Associated With the Need to Implement Case Management
Epidemiologic and clinical characteristics favoring implementation of in-depth case investigation, contact tracing, and/or case management	Effort to detect outbreaks or unusual clusters of cases (ie, pathogens commonly occurring in outbreaks; occurrence in atypical population, geographic, or seasonal distribution) Etiology or source of illness not defined Cases in vulnerable populations (long term care facilities and other institutional settings) Atypical pathogen (eg, viral hemorrhagic fever; toxigenic Corynebacterium diphtheriae). Illness is severe, communicable and/or associated with an environmental source or animal reservoir.	Person-to-person transmission or common source outbreaks Infections concentrated in marginalized populations (syndemics common) that may require additional support services Number of contacts manageable using CICT staff or subset of cases/contacts can be prioritized Longer serial interval allowing for contact tracing to occur before most transmission occurs Evidence supports contact tracing as being effective More severe clinical outcomes	Infections requiring longer or more complex treatment or prophylaxis Infections concentrated in marginalized populations (syndemics common) that may require additional support services Number of cases manageable using CICT staff or subset of cases can be prioritized Index cases have potential to benefit from intervention not directly related to infection for which investigation initiated (eg, HIV PrEP in index cases with syphilis) Evidence supports case management as being effective More severe clinical outcomes
Public health activities and interventions used to address problem	Facilitate treatment or PEP Communication to public and medical community Policy intervention or clinical guidance Informs development of new disease control strategy	CICT to identify contacts of cases and persons exposed to potential common source and follow-up with those persons. Quarantine of contacts is an important part of disease control. Case management (linkage of cases and contacts to care and support services) Treatment of cases or prophylaxis in contacts decreases morbidity and/or transmission	Linkage of cases to clinical or support services, adherence support Case isolation is an important part of disease control.
Examples	Emerging pathogens Severe communicable diseases (SARS-CoV-2; meningococcal disease, rabies, legionellosis) Certain foodborne illness (STEC, hepatitis A, shellfish-associated illness). Nosocomial Infections (MDRO) Outbreaks of syphilis and HIV in heterosexuals	Syphilis† HIV† TB Measles Meningococcus	Syphilis HIV TB Meningococcus

*Activities are not mutually exclusive and, in most instances, CICT involves varying amounts of each activity.

^†Contemporary case-finding through contact tracing in MSM is very low.

STEC, Shiga toxin-producing E. coli; MDRO, Multidrug-resistant organism.