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National Notifiable Diseases Surveillance System (NNDSS)

Description

The National Notifiable Diseases Surveillance System (NNDSS) provides weekly provisional information on the occurrence of diseases defined as notifiable by the Council of State and Territorial Epidemiologists.

Supplier

Centers for Disease Control and Prevention, Public Health Surveillance and Informatics Program Office (CDC/PHSIPO)

Data Years Available

1912-present

Periodicity

Weekly

Mode

State epidemiologists report cases of notifiable diseases to CDC, which tabulates these data weekly, and in annual summaries.

Selected Content

Data include the incidence of reportable diseases using uniform case definitions.

Population covered

Notifiable disease reports are received from health departments in the 50 states, 5 territories, New York City, and the District of Columbia.

Methodology

Notifiable disease surveillance is conducted by public health practitioners at local, state, and national levels to support disease prevention and control activities. The Council of State and Territorial Epidemiologists and CDC annually review the status of national infectious disease surveillance and recommend additions or deletions to the list of nationally notifiable diseases based on the need to respond to emerging priorities. Because reporting is currently mandated by law or regulation only at the local and state levels, the list of diseases that are considered notifiable varies slightly by state. State epidemiologists report cases of notifiable diseases to CDC, which tabulates and publishes these data in Morbidity and Mortality Weekly Report (MMWR) and in Summary of Notifiable Diseases, United States.

Response rate and sample size

N/A

Interpretation Issues

NNDSS data must be interpreted in light of reporting practices. If persons who have a reportable disease do not seek medical care from a health care provider, the case may not be reported. The degree of completeness of data reporting is also influenced by the diagnostic facilities available, the control measures in effect, public awareness of a specific disease, and the interests, resources, and priorities of state and local public health officials. Finally, factors such as changes in case definitions for surveillance, introduction of new diagnostic tests, or discovery of new disease entities can cause changes in disease reporting that are independent of the true incidence of disease.

References

National Center for Health Statistics. Health United States 2009: With Special Feature on Medical Technology. Hyattsville, Maryland. 2010; pp 469-470.