Nationally Notifiable Infectious Diseases and Conditions, United States: Annual Tables

TABLE 2b. Annual reported cases* of notifiable diseases, by region and reporting area, United States, U.S. Territories, and Non-U.S. Residents, 2020†
Data from some reporting areas may be incomplete due to the coronavirus disease 2019 (COVID-19) pandemic or due to post-reconciliation data updates that could not be confirmed or included in the final data set. Please see Note #9 and Note #10, respectively.
Reporting Area Arboviral diseases
La Crosse virus disease Powassan virus disease St. Louis encephalitis virus disease West Nile virus disease
Neuroinvasive Non-neuroinvasive Neuroinvasive Non-neuroinvasive Neuroinvasive Non-neuroinvasive Neuroinvasive Non-neuroinvasive
U.S. Residents, excluding U.S. Territories 84 4 19 1 14 2 558 172
New England — — 9 1 — — 15 6
Connecticut — — 2 — — — 5 3
Maine — — 1 — — — 1 —
Massachusetts — — 6 1 — — 9 3
New Hampshire — — — — — — — —
Rhode Island — — — — — — — —
Vermont — — — — — — — —
Middle Atlantic — — 6 — — 1 28 8
New Jersey — — 1 — — — 3 —
New York (excluding New York City) — — 1 — — — 12 3
New York City — — — — — — 6 1
Pennsylvania — — 4 — — 1 7 4
East North Central 34 3 4 — — — 76 9
Illinois 1 — — — — — 36 6
Indiana 1 — — — — — 3 —
Michigan — — — — — — 29 3
Ohio 30 3 — — — — 3 —
Wisconsin 2 — 4 — — — 5 —
West North Central — — — — — — 30 24
Iowa — — — — — — 2 1
Kansas — — — — — — 6 2
Minnesota — — — — — — — —
Missouri — — — — — — 1 —
Nebraska — — — — — — 9 6
North Dakota — — — — — — 2 5
South Dakota — — — — — — 10 10
South Atlantic 30 1 — — — — 58 9
Delaware — — — — — — — —
District of Columbia — — — — — — — —
Florida — — — — — — 44 7
Georgia 1 — — — — — 7 1
Maryland — — — — — — 1 —
North Carolina 21 — — — — — 1 —
South Carolina 1 — — — — — 4 —
Virginia 1 — — — — — 1 1
West Virginia 6 1 — — — — — —
East South Central 20 — — — — — 11 5
Alabama — — — — — — 7 2
Kentucky 5 — — — — — — —
Mississippi — — — — — — 4 3
Tennessee 15 — — — — — — —
West South Central — — — — 3 — 122 26
Arkansas — — — — — — 1 —
Louisiana — — — — — — 14 4
Oklahoma — — — — — — 6 1
Texas — — — — 3 — 101 21
Mountain — — — — 6 — 39 26
Arizona — — — — 6 — 7 4
Colorado — — — — — — 17 18
Idaho — — — — — — 5 1
Montana — — — — — — 1 —
Nevada — — — — — — — 1
New Mexico — — — — — — 7 1
Utah — — — — — — 1 1
Wyoming — — — — — — 1 —
Pacific — — — — 5 1 179 59
Alaska — — — — — — — —
California — — — — 5 1 179 56
Hawaii — — — — — — — —
Oregon — — — — — — — 1
Washington — — — — — — — 2
U.S. Territories — — — — — — — —
American Samoa — — — — — — — —
Commonwealth of Northern Mariana Islands — — — — — — — —
Guam — — — — — — — —
Puerto Rico — — — — — — — —
U.S. Virgin Islands — — — — — — — —
Non-U.S. Residents — — — — — — — —
Total 84 4 19 1 14 2 558 172
  • —: 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.
  • U: Unavailable — The data are unavailable.
  • * Cases are assigned to the reporting jurisdiction submitting the case to NNDSS if the case's country of usual residence is the United States, a U.S. territory, unknown, or country is 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 because this data element is only available in the HL7 generic version 2 and disease-specific message mapping guides. If a jurisdiction sends data in legacy formats, they are not able to send this information. For further information on interpretation of these data, see https://www.cdc.gov/nndss/data-statistics/readers-guides/.
  • † To calculate rates, use the populations provided in Table 8. Note that calculation of rates for the following conditions use population subsets presented in Table 8: Zika virus infection, congenital; Zika virus disease, congenital; Infant botulism; Congenital rubella syndrome; Perinatal Hepatitis B infection; Perinatal Hepatitis C infection; Haemophilus influenzae, invasive disease; Invasive pneumococcal disease; and Influenza-associated pediatric mortality. Also see Notes #3 and #7.
Notes:
  1. These are annual 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. Cases are reported by state health departments to CDC weekly. Because source datasets may be updated as additional information is received, statistics in publications based on that source data may differ from what is presented in these tables. Source datasets for the 2020 annual tables were officially closed on September 27, 2022.
  2. The list of national notifiable Infectious diseases and conditions for 2020 and their national surveillance case definitions are available by navigating to the Surveillance Case Definitions | CDC web page, selecting "2020" for the notifiable condition list year, checking "Infectious" conditions, and clicking "Get Notifiable List by Year". This list incorporates the Council of State and Territorial Epidemiologists (CSTE) position statements approved in 2019 by CSTE for national surveillance that were implemented in January 2020. Revised case definitions were implemented for the following conditions: plague, legionellosis, acute hepatitis C, spotted fever rickettsiosis, and pertussis. In addition, CSTE adopted the first coronavirus disease 2019 (COVID-19) national surveillance case definition on April 5, 2020, and they approved a revision to the COVID-19 national surveillance case definition, effective August 5, 2020. Publication criteria for the finalized 2020 data are available at https://wonder.cdc.gov/nndss/documents/2020_NNDSS_Publication_Criteria_03162022.pdf. See also Guide to Interpreting Provisional and Finalized NNDSS Data.
  3. Population estimates for incidence rates are July 1st, 2020, estimates obtained from the National Center for Health Statistics (NCHS) postcensal estimates of the resident population of the United States for April 1, 2010, to July 1, 2020, by year, county, single year of age (range: 0 to 85 years), bridged-race (white, black or African American, American Indian or Alaska Native, Asian, or Pacific Islander), Hispanic ethnicity (not Hispanic or Latino, Hispanic or Latino), and sex (Vintage 2020), prepared under a collaborative arrangement with the U.S. Census Bureau. Population estimates for states released September 21, 2021, are available at https://www.cdc.gov/nchs/nvss/bridged_race/data_documentation.htm. Population estimates for territories are the 2020 mid-year estimates from the U.S. Census Bureau International Data Base, accessed on March 15, 2022, at https://www.census.gov/data-tools/demo/idb/#/country?YR_ANIM=2022. The choice of population denominators for incidence is based on the availability of population data at the time of publication preparation.
  4. Annual tables for 2016 and later years are available on CDC WONDER.
  5. Annual summary reports from 1993–2015 are available as published in the Morbidity and Mortality Weekly Report.
  6. NNDSS annual tables since 1952 are available at CDC Stacks (once in CDC Stacks, select "Annual Reports" in the "Genre" box to the left).
  7. For most conditions, national incidence rates are calculated as the number of reported cases for each infectious disease or condition divided by the U.S. resident population for the specified demographic population or the total U.S. resident population, multiplied by 100,000. When a national notifiable infectious condition is associated with a specific age restriction, the same restriction was applied to the population in the denominator of the incidence rate calculation. In addition, population data from reporting jurisdictions in which the disease or condition was not reportable or not available were excluded from the denominator of the incidence rate calculations.

    Age restrictions in the numerator and denominator are applied for the following childhood conditions:

    • Zika virus disease, congenital (age restriction in numerator and denominator is <1 year)
    • Zika virus infection, congenital (age restriction in numerator and denominator is <1 year)
    • Haemophilus influenzae, invasive disease <5 years (age restriction in numerator and denominator is <5 years)
    • Invasive pneumococcal disease <5 years (age restriction in numerator and denominator is <5 years)
    • Influenza associated pediatric mortality (age restriction in numerator and denominator is <18 years)
    • Infant botulism (age restriction in numerator and denominator is <1 year)
    • Congenital rubella syndrome (age restriction in numerator and denominator is <1 year)
    • Perinatal hepatitis B infection (age restriction in numerator is ≤24 months, denominator is <24 months)
    • Perinatal hepatitis C infection (age restriction in numerator is ≤36 months, denominator is <36 months).

    Data for congenital syphilis are aggregated by the infant's year of birth. The rate for congenital syphilis is based upon the number of reported cases per 100,000 live births, using natality data for 2020 (National Center for Health Statistics Natality 2020, as compiled from data provided by the Vital Statistics Cooperative Program). Congenital syphilis cases are usually assigned to the mother's state of residence at the time of delivery. The mother's race and ethnicity are used for race- and ethnicity-specific rates of congenital syphilis cases.

  8. Surveillance data reported by other CDC programs might vary from data reported in these tables because of differences in 1) the date used to aggregate the data, 2) the timing of reports, 3) the source of the data, 4) surveillance case definitions, and 5) policies regarding case jurisdiction (i.e., which jurisdiction should submit the case notification to CDC).
  9. The following reporting areas may have incomplete data, due to technical or programmatic challenges while reconciling data during the COVID-19 pandemic: California, Guam, and Minnesota.
  10. The following reporting areas may have incomplete data due to updates made to their data after the 2020 reconciliation period ended and there was not sufficient time before publication of the annual tables to confirm the updated counts: Idaho, Kansas, Maryland, Vermont, and Virgin Islands.
  11. Of the reporting areas that submitted 2020 aggregate COVID-19 data to CDC, three did not submit probable cases. New York (excluding New York City) and Utah did not collect probable cases. U.S. Virgin Islands collected probable cases, but did not report them to CDC.
  12. Disease data presented in the 2020 tables reflect impacts of the COVID-19 pandemic, such as changes in exposure-related behavior, healthcare-seeking behavior, disease reporting, and public health investigations.
Suggested Citation: Acknowledgment:
  • CDC acknowledges the local, state, and territorial health departments that collected the data from a range of case ascertainment sources (e.g., healthcare providers, hospitals, laboratories) and reported these data to CDC's National Notifiable Diseases Surveillance System.