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Data Collection and Reporting

In order for CDC to collect and use public health surveillance data, the NNDSS staff works closely with state and local health departments; experts from CDC programs with prevention and control responsibilities; and partners, such as the Council of State and Territorial Epidemiologists (CSTE).  Together, they develop and implement consistent standards, tools, training, and technology to help ensure that disease reporting systems are integrated within each state.  They also help make sure that public health surveillance systems are interoperable with public health surveillance systems at CDC and other state and local health departments, as well as with health IT systems used by hospitals, laboratories, and private providers.  NNDSS provides National Electronic Disease Surveillance System (NEDSS) standards, tools, and resources to support reporting jurisdictions – state, local, territorial, and tribal health departments – to help them implement integrated and interoperable public health surveillance systems.  In an integrated system, a public health record is created to capture information about multiple occurrences of the same or different diseases in a given person over time.  An interoperable system can exchange information with other systems.

Notifiable Disease Surveillance Starts at State and Local Levels

CDC receives case notifications from 57 reporting jurisdictions.  Each state has laws requiring certain diseases be reported at the state level, but it is voluntary for states to provide information or notifications to CDC at the federal level.  The notifiable diseases data voluntarily shared by these 57 jurisdictions represents only a portion of the public health surveillance data that jurisdictions collect and use to make decisions and conduct public health activities in their communities (e.g., outbreak detection and control).  There are several important distinctions between a reportable disease and a notifiable disease.

  • It is mandatory that reportable disease cases be reported to state and territorial jurisdictions when identified by a health provider, hospital, or laboratory.  This type of required reporting uses personal identifiers and enables the states to identify cases where immediate disease control and prevention is needed.  Each state has its own laws and regulations defining what diseases are reportable.  The list of reportable diseases varies among states and over time.
  • It is voluntary that notifiable disease cases be reported to CDC by state and territorial jurisdictions (without direct personal identifiers) for nationwide aggregation and monitoring of disease data.  Regular, frequent, timely information on individual cases is considered necessary to monitor disease trends, identify populations or geographic areas at high risk, formulate and assess prevention and control strategies, and formulate public health policies.  The list of notifiable diseases varies over time and by state.  The list of national notifiable diseases is reviewed and modified annually by the CSTE and CDC.  Every national notifiable disease is not necessarily reportable in each state. In addition, not every state reportable condition is national notifiable.


A notifiable disease or condition is one for which regular, frequent, and timely information regarding individual cases is considered necessary for the prevention and control of the disease or condition. Data are collected through NNDSS, which is neither a single surveillance system nor a method of reporting. Rather, it is a “system of systems,” which is coordinated by CDC at the national level across disease-specific programs to optimize data compilation, analysis, and dissemination of notifiable disease data. Monitoring surveillance data enables public health authorities to detect sudden changes in disease or condition occurrence and distribution, identify changes in agents and host factors, and detect changes in health-care practices. National-level surveillance data are compiled from case notification reports of national notifiable diseases and conditions submitted from the state, territory, and selected local health departments to CDC.

Cases are first identified through reports of diseases, conditions, and outbreaks from the local level to the state or territory. Legislation, regulation, or other rules in those jurisdictions require health-care providers, hospitals, laboratories, and others to provide information on reportable conditions to public health authorities or their agents. Case reporting at the local level protects the public’s health by ensuring the proper identification and follow-up of cases. Public health workers ensure that persons who are already ill receive appropriate treatment; trace contacts who need vaccines, treatment, quarantine, or education; investigate and control outbreaks; eliminate environmental hazards; and close premises where disease transmission is believed to be ongoing.

Although disease and condition reporting is mandated at the state, territory, and local levels by legislation or regulation, state and territory notification to CDC is voluntary. All U.S. state health departments, five territorial health departments, and two local health departments (New York City and District of Columbia) voluntarily notify CDC about national notifiable diseases and conditions that are reportable in their jurisdictions; the data in the case notifications that CDC receives are collected by staff working on reportable disease and condition surveillance systems in local, state, and territorial health departments.

The list of national notifiable diseases, conditions, and outbreaks is revised periodically. Conditions are added to the list as emerging pathogens, environmental hazards, or conditions emerge as public health concerns.  Conditions are deleted from the list when surveillance is not found to be useful. Public health officials at state and territorial health departments collaborate with CDC staff in determining which diseases, conditions, and outbreaks should be considered nationally notifiable. CSTE, with input from CDC, makes recommendations annually for additions and deletions to the list. Similar to local public health officials, CDC uses these data to monitor trends; develop, implement and maintain programs; allocate resources; and assess the effectiveness of prevention and control efforts. The list of diseases and conditions considered reportable in each jurisdiction varies over time and across jurisdictions. Current and historical national public health surveillance case definitions used for classifying and enumerating cases consistently at the national level across reporting jurisdictions are available at

Form Approved

OMB No. 0920-0728

Expiration Date: 04/30/2023

The public reporting burden of this collection of information is estimated to average 20 minutes per response for states, cities, and territories that automate case notification, 2 hours for states and cities that do not automate, and 20 minutes for territories and freely associated states that do not automate. This includes the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. An agency may not conduct or sponsor, and a person is not required to respond to all collection of information unless it displays a currently valid OMB control number. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to – CDC/ATSDR Reports Clearance Officer; 1600 Clifton Road NE, MS D-74, Atlanta, Georgia 30329 ATTN: PRA (0920-0728).