U: Unavailable — The reporting jurisdiction was unable to send the data to CDC or CDC was unable to process the data.
-: No reported cases — The reporting jurisdiction did not submit any cases to CDC.
N: Not reportable — The disease or condition was not reportable by law, statute, or regulation in the reporting jurisdiction.
NN: Not nationally notifiable — This condition was not designated as being nationally notifiable.
NP: Nationally notifiable but not published.
NC: Not calculated — There is insufficient data available to support the calculation of this statistic.
Cum: Cumulative year-to-date counts.
Max: Maximum — Maximum case count during the previous 52 weeks.
* Case counts for reporting year 2021 are provisional and subject to change.
Cases are assigned to the reporting jurisdiction submitting the case to NNDSS, if the case's country of usual residence is the U.S.,
a U.S. territory, unknown, or null (i.e. country not reported); otherwise, the case is assigned to the 'Non-U.S. Residents' category.
Country of usual residence is currently not reported by all jurisdictions or for all conditions.
For further information on interpretation of these data, see
†Previous 52 week maximum and cumulative YTD are determined from periods of time when the condition was reportable in the jurisdiction (i.e., may be less than 52 weeks of data or incomplete YTD data).
§ Includes data for old world hantavirus infections, such as Seoul virus infections. Prior to 2015, this condition was not nationally notifiable and data for this condition was not submitted to CDC's National Notifiable Diseases Surveillance System (NNDSS).
¶ Includes data for Andes virus infections.
These are weekly cases of selected infectious
national notifiable diseases, from the
National Notifiable Diseases Surveillance System (NNDSS).
NNDSS data reported by the 50 states, New York City, the District of Columbia,
and the U.S. territories are collated and published weekly as numbered tables.
Cases reported by state health departments to CDC for weekly publication are
subject to ongoing revision of information and delayed reporting.
Therefore, numbers listed in later weeks may reflect changes made to
these counts as additional information becomes available.
Case counts in the tables are presented as published each week.
Guide to Interpreting Provisional and Finalized NNDSS Data.
Weekly tables since 1996 are available on
Weekly tables for 1952–2017 published in the Morbidity and Mortality Weekly Reports (MMWR) are available at CDC Stacks MMWR,
and weekly tables starting in 2018 are available at CDC Stacks NNDSS
(once in CDC Stacks NNDSS select "Weekly Tables" in the "Genre" box at the left).
The list of national notifiable infectious diseases and conditions and their national surveillance case definitions are
available at https://ndc.services.cdc.gov/. This list incorporates the Council of State and Territorial
Epidemiologists (CSTE) position statements approved by CSTE for national surveillance.
Centers for Disease Control and Prevention. National Notifiable Diseases Surveillance System,
Weekly Tables of Infectious Disease Data. Atlanta, GA. CDC Division of Health Informatics and Surveillance.
Available at: https://www.cdc.gov/nndss/data-statistics/index.html.
CDC acknowledges the local, state, and territorial health departments that collected the data from a range of case ascertainment
sources (e.g., health-care providers, hospitals, laboratories) and reported these data to
CDC's National Notifiable Diseases Surveillance System.