How NNDSS Supported the COVID-19 Response


The National Notifiable Diseases Surveillance System (NNDSS) supported our nation’s response to the unprecedented threat of coronavirus disease 2019 (COVID-19). Along with our partners in state, local, and territorial public health departments and disease programs at CDC, our team worked to ensure data about cases of COVID-19 across the nation were received, processed, and sent to the disease experts at CDC. These experts used the information to better understand, track, and respond to the pandemic and improve national surveillance.

Here are some of the things NNDSS did behind the scenes to provide comprehensive, timely, and high-quality data for public health decision making:

  • We added a new event code for COVID-19 for public health departments’ use when notifying CDC of cases of COVID-19. Each disease or condition reported to NNDSS is assigned an event code. Event codes  are used by local, state, and federal surveillance information systems to help simplify storage and retrieval of information about cases of nationally notifiable or state reportable diseases or conditions.
  • We worked with our partner, the Council of State and Territorial Epidemiologists, to ensure that state, local, and territorial public health departments have the information they need to classify cases of COVID-19 consistently. Our team posted the COVID-19 surveillance case definition on the NNDSS Surveillance Case Definitions webpage. A case definition is a set of uniform criteria used to define a disease for public health surveillance and reporting purposes and helps public health classify and count cases consistently across reporting jurisdictions.
  • We developed and posted a COVID-19 message mapping guide (MMG) on the NNDSS Technical Resource Center. The MMG provides guidance for how public health departments should package and transmit case notification data to CDC.
  • We updated our Message Validation, Processing, and Provisioning System, or MVPS, to be able to receive data about COVID-19 cases from state, local, and territorial public health departments. We also enhanced processing capacity to ensure that MVPS was prepared for the increase in data. When public health departments started sending COVID-19 case notification messages to CDC, MVPS was able to process 10 times the volume of data compared to the pre-COVID-19 period.
  • We provided technical assistance through our partner, the Association of Public Health Laboratories, to help state, local, and territorial public health departments send their COVID-19 data to CDC.
  • We sent these critical data to disease experts at CDC and to the CDC Emergency Operations Center daily for use in national COVID-19 surveillance and the CDC COVID-19 pandemic response.

In support of the CDC Public Health Data Modernization Initiative, NNDSS will continue to look for ways to modernize our tools, technology, and strategy and to improve the quality and timeliness of the data we receive and provide. Modernization of public health data and IT systems was central to the nation’s efforts to respond to the COVID-19 global pandemic—and to strengthen preparedness for future public health threats.