Key points
- The National Notifiable Diseases Surveillance System (NNDSS) creates weekly data, known as provisional data, and annual data, known as finalized data.
- Learn about the differences between provisional and finalized data at the Centers for Disease Control and Prevention.
About weekly tables (provisional)
Weekly data are considered provisional data. Provisional data are initially collected locally as a result of state, territorial, and local legislation and regulations that require healthcare providers, medical laboratories, and other entities to submit data on reportable conditions to state and local public health departments. The reportable conditions vary depending upon each jurisdiction's health priorities. The reporting jurisdictions voluntarily submit case notifications for the national notifiable conditions to CDC. NNDSS data are considered provisional and subject to change each week until the data are reconciled and verified with the state and territorial data providers to be the final official incidence counts for a given notifiable condition and year. Cumulative counts of cases presented each week can increase or decrease as additional information becomes available and counts are updated. In any given year, for most conditions, cumulative provisional case counts and rates do not match finalized case counts and rates.
Notifiable infectious disease data tables
The data for national notifiable infectious diseases and conditions are aggregated weekly for all conditions.
Weekly data are considered provisional data. Annual data are considered finalized data. Finalized data are created within approximately 6 months after the end of the calendar year.
Weekly tables
- WONDER Weekly Tables of Infectious Diseases (1996 to present)
- DATA.CDC.gov Provisional Weekly Infectious Disease Data (2014 to present)
- MMWR Weekly Tables of Infectious Diseases (1993 to 2017)
- CDC Stacks Collections of Weekly Infectious Disease Tables (1951 to present)
Annual tables
- WONDER Annual Tables of Infectious Diseases and Conditions (2016 to present)
- MMWR Summary of Notifiable Infectious Diseases and Conditions (1993-2015) NOTE: Beginning in 2016, NNDSS finalized data were published on CDC WONDER.
- CDC Stacks Collections of Annual Tables of Infectious Diseases and Conditions (1952 to present) Hint: once in CDC Stacks, go to left side of screen and select "Annual Reports" from "Narrow Results", "Genre".
Using and interpreting data
Readers’ guides
CDC provides Readers’ Guides to assist with understanding the weekly and annual National Notifiable Diseases Surveillance System (NNDSS) data tables. These documents provide data table descriptions, content overview, interpretation guidance, and other details.