FoodCORE SSL Metrics
SSL metrics apply to Salmonella, Shiga toxin-producing Escherichia coli (STEC), Listeria, Shigella, and Campylobacter (reporting for Shigella and Campylobacter is optional). The FoodCORE performance metrics are a list of measurable activities covering diverse aspects of outbreak response. These activities span from outbreak surveillance and detection through investigation, response, control, and prevention measures. Using the metrics, each center provides data about the burden, timeliness, and completeness of foodborne disease activities related to the key areas of activity. Data for all years of the FoodCORE program are available.
Isolate/Specimen-based Metrics
Rationale: The intent of these metrics is to evaluate the timeliness and completeness/availability of laboratory surveillance and subtyping data for Salmonella, Shiga toxin-producing Escherichia coli (STEC), Listeria, Shigella, and Campylobacter. These metrics can be used to determine if there are gaps in the laboratory isolate handling and testing processes. If gaps are identified, knowing the detailed circumstances around the gap will help develop targeted actions to address them specifically.
Case-based Metrics
Rationale: The intent of these metrics is to evaluate the timeliness and completeness/availability of epidemiologic data for reported cases. These metrics can be used to determine if there are gaps in the epidemiologic interviewing process. If gaps are identified, knowing the detailed circumstances around the gap will help develop targeted actions to address them specifically.
Investigation-based Metrics
Rationale: The intent of these metrics is to evaluate epidemiologic activity related to cluster and outbreak monitoring, evaluation, and investigation. These metrics can be used to determine if there are gaps in cluster and outbreak investigation. If gaps are identified, knowing the detailed circumstances around the gap will help develop targeted actions to address them specifically.
All measurements of time are in median days: Measurements will exclude weekend days. For laboratory time measurements, only isolates subtyped at the PHL should be included.
Isolate/Isolate-yielding specimen: This will include all isolates (human, food, environmental, etc.) submitted to PHL and isolates recovered from specimen submitted to PHL. This can be further broken down to report total number of each category of isolates (human, food, environmental, etc.).
Primary isolates and/or primary isolate-yielding specimen: To be limited to the first or representative isolate or sample for each case or testing unit for any non-human isolates (i.e., isolates that are intended to be part of a subtyping workflow, such as whole genome sequencing). Any samples that were collected but not processed or tested can be de-duplicated and not counted as a primary isolate. If multiple samples are from the same source, the primary isolates from each of the samples for which you completed testing can be counted.
Laboratory confirmed, probable, and suspect cases: Refer to NNDSS case definitions for each pathogen
Complete demographic data: To include State, County, Birth Month, Birth Year, Sex, Race
Exposure history: To include an interview (of any format) that assesses exposures prior to onset of illness, via an open-ended exposure history, or via a list of potential exposures. The key factor to be considered an exposure history is an interview that goes beyond assessment of high-risk settings and prevention education to ascertain food consumption/preference, or other exposure data.
Cluster: Two or more cases of infection where the number of cases meets one or more of the following criteria:
- The number of isolates/cases represent an increase over the expected baseline (as determined by PulseNet definition or other subtyping criteria)
- Demographic or other epidemiologic characteristics among cases indicate some deviation from expected values for the region (and is consistent with subtyping information)
- There is a non-human isolate that would indicate a potential source of human infections
- In the absence of meeting the above criteria in a catchment area, a case-patient should be considered cluster-associated if the above criteria are met when including isolates from other jurisdictions or catchment areas.
In the absence of meeting any of the above criteria, ill persons should be considered cluster-associated if there are demographic or epidemiologic indications of a common source of infection even without laboratory subtyping data to link cases.
This definition also includes clusters that may be defined as outbreaks in your jurisdiction.
Investigation: Any active epidemiologic follow-up resulting from the identification of a cluster. This could be initiating contact with a case (or the public health authority under whose jurisdiction a case falls) to ascertain direct case-based epidemiologic data, or active review of previously collected case-based data for cases later identified as cluster-associated.
Notification: Report of a case or cluster (depending on the metric) to epidemiology staff, i.e., when epidemiology staff first were made aware of a specific case or an identified cluster. This could be via routine communication such as a laboratory report or accessing a database, or via direct complaints, reports from another health authority (local, other state, federal, etc.), media report, or other means of communication.
Analytic epidemiologic study: A systematic, statistical analysis against a comparison group or within a cohort to test a hypothesis
Vehicle/Source Identified:
SUSPECT vehicle/source clusters: Clusters of infection where investigational and/or laboratory data indicate a likely source/vehicle of infection without confirmation: vehicle is a known risk factor, established errors in food preparation, or reported consumption by a high proportion of cluster-associated cases.
CONFIRMED vehicle/source clusters: Clusters of infection where the etiologic agent has either been cultured from the vehicle or the vehicle has been statistically implicated in an analytic study.
Control measure: to include interventions such as exclusion of an ill person(s) from high risk setting, remediation or closure of an establishment linked to illness, educational campaigns during daycare outbreaks, etc. To be considered a control measure, activities should extend beyond the routine educational component of an interview or exposure assessment.
Public health action: to include media, public messaging (web updates, press release, etc.), or regulatory action (recall, hold, etc.). To be considered a public health action, activities should extend beyond the routine investigation activities and reach at-risk individuals beyond identified cases. A public health action should be included in the metrics if the FoodCORE Center was directly involved in the action, or is aware that a public health action was taken during a multijurisdictional investigation. For example, if CDC produces public messaging during a multistate outbreak investigation that a FoodCORE Center is involved in, that investigation would be associated with a public health action for the purposes of the metrics.