Distributed data processing for public health surveillance

Lazarus, Ross; Yih, Katherine; Platt, Richard

When unexpectedly high counts of particular syndromes are detected in geographically defined areas, the datacenter automatically generates electronic alerts, which are automatically routed to appropriate public health authorities. For example, in Massachusetts, electronic messages are automatically sent to the Massachusetts Alert Network within minutes of detection, where they are automatically and immediately forwarded to the appropriate Public Health personnel for follow up. Available alert delivery methods in the Massachusetts system range from email through to an automated telephone text-to-speech delivery system. Responders can configure the alert delivery method for each type of alert they have subscribed to. This alerting system is independent of our distributed system, but in practice, the ready availability of reports in electronic format containing both fully and partially identifiable clinical data for all cases comprising any particular period or syndrome makes the task of the clinical responder much simpler whenever a query is received from a public health official. Electronic reports, containing clinical information and optionally, full identifiers for all encounters can be generated as required, at the provider's site, from where they can immediately be made available to public health agencies. In the NDP's current operational mode (see Figure 1 ), a public health official calls a designated clinical responder to obtain this information. Table 2 ). The "narrow" version, which contains fewer identifiers, provides each patient's five-year age group instead of date of birth and does not include the physician ID or medical record number (Table 3) . At the provider's discretion, the clinical responder can provide the "narrow" list corresponding to the cases of interest to the public health department. If on this basis public health officials decide that further investigation is warranted, they can call the clinical provider and request a review of medical records, identifying the cases of interest by date and an index number (unique within date) in the narrow line list. The clinician finds the medical record number by looking up the date and index number in the wide line list and then accesses the record itself through the usual HMO-specific means. Resources to support clinical responders were provided through our NDP grant to participating data providers.