Notice to Data Users and Publication Criteria

Errata

March 2025

If NNDSS weekly tables on http://data.cdc.gov were accessed before March 24, 2025, please be aware that there was an issue with the data presented. Specifically, counts of four digits or larger were incorrectly displayed as null values. The problem has since been resolved and the tables have retroactively been updated. Please review the updated data to ensure accurate information is used.

January 2025

Beginning with the 2025 weekly NNDSS tables, the following changes were made:

• Case counts include anthrax caused by any Bacillus spp. that produces anthrax toxin, not just B. anthracis and B. cereus, to align with the approved CSTE position statement 24-ID-01. The weekly tables count summarizes all sub-classifications of anthrax: cutaneous anthrax, ingestion anthrax, inhalation anthrax, injection anthrax, and welder's anthrax.
• Babesiosis are no longer included in the weekly tables but will remain in the annual tables.
• Coronavirus disease 2019 (COVID-19) is no longer nationally notifiable starting in 2025 and data for this condition will not be included in the annual 2024 NNDSS tables. Data for COVID-19 have not previously been included in the weekly tables, but data is available on the COVID Data Tracker web site and historical case surveillance data is available via public use datasets at data.cdc.gov.
• For Leprosy (Hansen's disease), confirmed and probable cases are published to align with the approved CSTE position statement 24-ID-05, whereas in previous years, only confirmed case classification status was captured and published.
• Novel influenza A case counts include both confirmed and probable cases to align with the approved CSTE position statement 24-ID-09, whereas in previous years, only confirmed cases were published. The updated novel influenza A virus infections case definition was implemented on September 29, 2024.
• Rift Vally fever virus is a new nationally notifiable condition starting in 2025 and was added to the NNDSS weekly and annual tables.
• For viral hemorrhagic fevers, only confirmed cases are published to align with the approved CSTE position statement 24-ID-12, whereas in previous years, confirmed and suspect cases were published.
• For rubella, only confirmed cases are published to align with the approved CSTE position statement 24-ID-10, whereas in previous years, confirmed and unknown case classification statuses were published.
• Refer to the NNDSS case definition website for new and revised surveillance case definitions. The Council of State and Territorial Epidemiologists (CSTE) approved revised 2025 case definitions for anthrax, babesiosis, brucellosis, coronavirus disease 2019 (COVID-19), leprosy (Hansen's disease), leptospirosis, novel influenza A virus infections, rubella, and viral hemorrhagic fevers.
• As with prior years, conditions under standardized surveillance (CSS) are not included in the weekly NNDSS tables. New CSS are Chagas Disease and firearm-related injury.

January 2024

Beginning with the 2024 weekly NNDSS tables, the following changes were made:

• Invasive Cronobacter infection among infants is a new nationally notifiable condition starting in 2024 and was added to the NNDSS tables.
• Zika virus non-congenital and congenital infection (without disease) are no longer nationally notifiable and will no longer be included in the 2024 NNDSS tables.
• Monkeypox cases are displayed in the 2024 NNDSS tables and include confirmed and probable cases.
• While COVID-19 has been nationally notifiable since 2022, data for this condition are not included in the weekly 2024 NNDSS tables. Case surveillance data (including deaths) and associated demographic information derived from these data will remain available via public use datasets at data.cdc.gov.
• Ehrlichiosis and anaplasmosis (Anaplasma phagocytophilum, Ehrlichia ewingii, and Ehrlichia chaffeensis infections) are no longer included in the weekly tables but will remain in the annual tables. Undetermined ehrlichiosis/anaplasmosis is no longer nationally notifiable and is not included in the NNDSS tables.
• Confirmed and probable cases of acute hepatitis B, chronic hepatitis B, acute hepatitis C, and chronic hepatitis C are included in the 2024 weekly tables. Weekly publication changes for hepatitis viral infections include the addition of:
  • Hepatitis B, acute probable cases
  • Hepatitis B, chronic probable cases
  • Hepatitis C, chronic confirmed and probable cases
• Refer to the NNDSS case definition website for new and revised surveillance case definitions. The Council of State and Territorial Epidemiologists (CSTE) approved revised 2024 case definitions for anaplasmosis; ehrlichiosis; hepatitis B infection; mumps; paralytic and nonparalytic poliovirus infection; varicella disease; and Zika virus disease. The full CSTE position statements can be found on the CSTE position statement archive website.
• As with prior years, conditions under standardized surveillance (CSS) are not included in the weekly NNDSS tables. New CSS are toxoplasmosis and congenital cytomegalovirus infections. Neonatal abstinence syndrome (NAS) is an updated CSS.

July 2023

Due to data processing issues at CDC, data for some conditions for South Dakota are marked as unavailable (U) or not calculated (NC) for weeks 28 and 29.

February 2023

Due to data processing issues at CDC, data for Ohio are marked as unavailable (U) or not calculated (NC) for week 6.

January 2023

Beginning with the 2023 weekly NNDSS tables, the following changes were made:

• The 2023 weekly NNDSS tables were reformatted to display nationally notifiable diseases and conditions alphabetically in a single menu format, as opposed to being displayed alphabetically in a distributed fashion across sequentially numbered tables.
• Melioidosis; Candida auris, screening; carbapenemase-producing organisms (CPO), clinical; and CPO, screening are new nationally notifiable conditions which have been added to the weekly NNDSS tables.
• Carbapenem-resistant Enterobacteriaceae (CP-CRE) has been removed from the 2023 NNDSS tables, because it has been replaced with CPO. CP-CRE is considered a subset of CPO and thus CPO has replaced CP-CRE in the NNDSS tables.
• Starting week 1 of 2023, animal rabies data will no longer be presented in the weekly NNDSS data tables. Animal rabies will only be presented in the annual NNDSS data tables.
• While monkeypox and COVID-19 were nationally notifiable in 2022 and continue to be nationally notifiable, data for these conditions will not appear in the weekly 2023 NNDSS tables until the public health response for these conditions has transitioned to routine surveillance methods. During the public health response, data for monkeypox is available on CDC's Monkeypox web site and data for COVID-19 can be found on the COVID Data Tracker web site.
• Refer to the NNDSS case definition web site for new and revised surveillance case definitions. The Council of State and Territorial Epidemiologists (CSTE) approved revised 2023 case definitions for COVID-19; coccidioidomycosis; Candida auris, clinical; gonorrhea; and animal rabies. CSTE approved new case definitions in 2023 for melioidosis; CPO, clinical; CPO, screening; and Candida auris, screening. In addition, the new 2022 monkeypox case definition will continue to be used in 2023.

Errata

June 2023

The export files (.txt version) for the 2023 NNDSS weekly tables weeks 1-18 are missing the non-numeric values that are displayed in the corresponding .html version. This causes the data in the export files to be shifted to an incorrect column label. For the correct data display, the reader should refer to the .html version of the data tables for the 2023 NNDSS weekly tables weeks 1-18. The export files are correct for the 2023 NNDSS weekly tables weeks 19 and beyond.

February 2022

Effective Tuesday, February 22, 2022, the 2022 data presented in the NNDSS Weekly Tables on Data.CDC.gov are now available in a single table. This consolidates 42 separate tables, simplifying data extraction. Current NNDSS weekly case counts are now available for all notifiable conditions in one place at https://data.cdc.gov/NNDSS/NNDSS-Weekly-Data/x9gk-5huc.

January 2022

The NNDSS data platform experienced processing delays of some case notifications since January 14, 2022. Additionally, generation of aggregate counts for publication was delayed. These factors may impact the published counts for weeks 2 and 3 of 2022.

January 2022

In 2021, the NNDSS web site moved to https://www.cdc.gov/nndss/. This change impacts where to find supporting documentation and the citation in previously published tables. Specifically, the URLs have changed for the following resources:

1. NNDSS: now https://www.cdc.gov/nndss/ (previously https://wwwn.cdc.gov/nndss/)
2. Infectious tables - see Using and Interpreting Data: now https://www.cdc.gov/nndss/data-statistics/infectious-tables/index.html (previously https://wwwn.cdc.gov/nndss/infectious-tables.html)
3. Readers' Guides: now https://www.cdc.gov/nndss/data-statistics/readers-guides/
4. Five Year Weekly Average: now https://ndc.services.cdc.gov/wp-content/uploads/5yearweeklyaverage.pdf (previously https://wwwn.cdc.gov/nndss/document/5yearweeklyaverage.pdf)
5. Technical Resource Center: now https://www.cdc.gov/nndss/trc/ (previously https://wwwn.cdc.gov/nndss/downloads.html)
6. Surveillance Case Definitions: now https://ndc.services.cdc.gov (previously https://wwwn.cdc.gov/nndss/conditions/)
7. Provisional National Notifiable Diseases Surveillance Data: now https://ndc.services.cdc.gov/wp-content/uploads/ProvisionalNationaNotifiableDiseasesSurveillanceData20100927.pdf (previously https://wwwn.cdc.gov/nndss/document/ProvisionalNationaNotifiableDiseasesSurveillanceData20100927.pdf)
8. MMWR Weeks Fact Sheet: now https://ndc.services.cdc.gov/wp-content/uploads/2021/02/MMWR_Week_overview.pdf (previously http://wwwn.cdc.gov/nndss/document/MMWR_Week_overview.pdf)
9. MMWR Weeks Calendar: now https://ndc.services.cdc.gov/event-codes-other-surveillance-resources/ (previously http://wwwn.cdc.gov/nndss/script/downloads.aspx)

January 2022

The Council of State and Territorial Epidemiologists approved revised national surveillance case definitions in 2021 for Chlamydia trachomatis infection, Lyme disease, and the Viral Hemorrhagic Fevers that will be applied to the 2022 NNDSS data. In addition, Chapare hemorrhagic fever was added to the list of Viral Hemorrhagic Fevers in 2022. Beginning with the 2022 NNDSS data, the following print criteria changes will be implemented in the weekly and annual tables: a) the print criteria for Chlamydia trachomatis infection will change from all reported cases to confirmed cases only; and, b) the print criteria for the Viral Hemorrhagic Fevers will change from confirmed cases only to confirmed and suspect cases. Note that Lyme disease data are only published in the annual NNNDSS tables and in 2022, CDC will continue to publish confirmed and probable Lyme disease cases in those tables.

December 2021

Case counts for measles, mumps, pertussis, and rubella for week 49 of 2021 are erroneously elevated in some jurisdictions due to the inclusion of records that were classified as not a case.

December 2021

Improvements in data processing at CDC were applied to 2020 and 2021 data beginning with the tables published for week 47 of 2021. Case count changes between tables published for week 46 and week 47 may be due to changes in data processing rules and not due to changes in disease levels.

February 2021

Due to data processing issues at CDC, data for the following jurisdictions may be incomplete for week 7: Alaska, Arizona, California, Connecticut, Delaware, Florida, Hawaii, Louisiana, Maryland, Michigan, Missouri, North Dakota, New Hampshire, New York City, Oregon, Pennsylvania, and Rhode Island.

January 2021

In 2020, the Council of State and Territorial Epidemiologists (CSTE) approved the addition of coronavirus disease 2019 (COVID-19) to the list of nationally notifiable conditions. Data for COVID-19 are not currently published in either the 2020 or the 2021 weekly NNDSS tables, but instead are accessible here: https://covid.cdc.gov/covid-data-tracker/#datatracker-home. CSTE adopted the first 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.

Errata

February 2021

In Table 1n of the 2021 NNDSS weekly tables for week 1 only, data for Haemophilus influenzae in children <5 years categorized as "non-b serotype" and "unknown serotype" were updated on 02/26/2021 to correct the data associated with these two serotype categories. The original version of the tables incorrectly displayed data for "non-b serotype" in the "unknown serotype" column and incorrectly displayed data for "unknown serotype" in the "non-b serotype" column. The data are corrected now.

September 2020

Tuberculosis data included in the 2020 weekly NNDSS Table 1jj for weeks 4-31 are incorrect for New York City; the Middle Atlantic region total; U.S. Residents, excluding U.S. Territories total; and the grand total, due to data processing issues.

September 2020

Tuberculosis data included in the 2020 weekly NNDSS Table 1jj for weeks 32-33 are incorrect for the U.S. Residents, excluding U.S. Territories total and the grand total, due to data processing issues.

August 2020

Data for all diseases and conditions from Texas for 2019 and 2020 published in the 2020 week 32 NNDSS tables are incomplete, except for the arboviral diseases, congenital syphilis, and tuberculosis, due to a data processing issue at CDC.

August 2020

Data from California, published in the 2020 weekly NNDSS tables for week 29 for years 2019 and 2020, were incomplete when originally published on July 24, 2020. On August 4, 2020, incomplete case counts were replaced with a "U" indicating case counts are not available for specified time periods. This change impacted data for the following conditions and tables:

• campylobacteriosis (table 1f)
• carbapenemase-producing carbapenem-resistant Enterobacteriaceae, chancroid, and Chlamydia trachomatis infection (table 1g)
• coccidioidomycosis (table 1h)
• gonorrhea and Haemophilus influenzae invasive disease (table 1m)
• Haemophilus influenzae invasive disease (table 1n)
• hepatitis A acute and hepatitis B acute (table 1p)
• hepatitis C acute (table 1q)
• hepatitis C perinatal infection (table 1r)
• listeriosis (table 1u)
• measles (table 1v)
• meningococcal disease (tables 1w and 1x)
• mumps (table 1y)
• pertussis (table 1z)
• shigellosis (table 1ff)
• syphilis congenital and syphilis primary and secondary (table 1hh)

January 2020

Beginning in 2020, tuberculosis data will appear in the weekly NNDSS tables. Spotted fever rickettsiosis will no longer appear in the weekly NNDSS tables, however it will continue to be published in the annual NNDSS tables. The Council of State and Territorial Epidemiologists approved new surveillance case definitions for the following nationally notifiable infectious diseases: acute hepatitis C, chronic hepatitis C, pertussis, plague, legionellosis, and spotted fever rickettsiosis. These case definitions will be applied to new cases in surveillance year 2020. There were no new nationally notifiable conditions added to the NNDSS, as a result of approved 2019 CSTE position statements.

Errata

February 2021

In Table 1n of the 2020 NNDSS weekly tables for weeks 1-53, data for Haemophilus influenzae in children < 5 years categorized as "non-b serotype" and "unknown serotype" were updated on 02/26/2021 to correct the data associated with these two serotype categories. The original version of the tables incorrectly displayed data for "non-b serotype" in the "unknown serotype" column and incorrectly displayed data for "unknown serotype" in the "non-b serotype" column. The data are corrected now.

February 2020

Measles data for weeks 1-4 (in Table 1v) were updated on 02-28-2020 to correct the classification of imported and indigenous. Measles is considered imported if the disease was acquired outside of the United States and is considered indigenous if the disease was acquired anywhere within the United States or it is not known where the disease was acquired.

January 2019

The following changes were made to the weekly 2019 tables of nationally notifiable infectious diseases and conditions:

• The previous Table 1 format (which displayed infrequently reported notifiable diseases) was retired and data for all conditions in that table (except for diphtheria) are displayed using the weekly Table 2 format. Table 2 was renamed to Table 1.
• The 2019 NNDSS data in the new Table 1 are stratified by U.S. Residents, excluding U.S. Territories; U.S. Territories; and non-U.S. Residents; based upon the reported 'country of usual residence' for the case. This stratification is not applied to the 2018 NNDSS data in the 2019 table.
• The previous 52 week median statistic is no longer displayed, but the previous 52 week maximum and cumulative year-to-date counts are retained.
• Changes to the new Table 1 as a result of approved 2018 Council of State and Territorial Epidemiologists position statements include the following:
  • 'Candida auris, clinical cases' was added as a new nationally notifiable disease.
  • Salmonella Paratyphi infection and Salmonella Typhi infection replaced Paratyphoid fever and Typhoid fever, respectively.
  • Salmonellosis (excluding S. Typhi infection and S. Paratyphi infection) replaced Salmonellosis (excluding paratyphoid fever and typhoid fever).
  • Carbapenemase-producing carbapenem-resistant Enterobacteriaceae (CP-CRE) represents a consolidation of CP-CRE species Klebsiella spp, CP-CRE E. coli, and CP-CRE Enterobacter spp.
• The quarterly Tuberculosis Table 3 was renamed Table 2.

Figure 1 only includes data among U.S. residents (and therefore excludes data among U.S. Territories and non-U.S. residents).

October 2019

In 2019, CDC undertook a critical review of the content and method used to create Figure 1. Input from jurisdictions through the Council of State and Territorial Epidemiologists (CSTE) and from CDC programs was sought to determine usefulness and desire to maintain the figure. A determination was made that due to the limited usefulness of Figure 1, it will no longer be published as of the first week in surveillance year 2020.

November 2019

Software data processing failures resulted in incomplete weekly case counts for all 2019 tables for weeks 42 through 46.

November 2019

Software data processing failures resulted in incomplete weekly case counts in Tables 1a - 1pp and in Figure 1 for weeks 42 through 46 of the 2019 data.

December 2019

Starting week 1 of 2020, tuberculosis data will be presented in Table 1 and Table 2 will be discontinued.

March 2020

Measles 2019 data in Table 1v for weeks 1-51 were updated to remove the stratification of cases by imported and indigenous case classification status. Please see week 52, 2019 data for measles cases stratified by imported and indigenous status.

Errata

February 2020

Measles data for week 52 of the 2019 data (Table 1v) were updated on 02-28-2020 to correct the classification of imported and indigenous. Measles is considered imported if the disease was acquired outside of the United States and is considered indigenous if the disease was acquired anywhere within the United States or it is not known where the disease was acquired.

March 2022

The following footnote is missing in Table 1u for listeriosis for weeks 1-14:§ Before 2019, listeriosis cases in neonates less than or equal to 60 days of age were counted as one case in a mother-infant pair. Beginning in 2019, maternal and neonatal listeriosis cases are being counted separately.

January 2018

Beginning with the 2018 NNDSS data, there are a number of changes to the NNDSS display of weekly data.

• Non-congenital Zika virus disease was removed from Table I and added to Table 2.
• Paratyphoid fever was added to Table 1. Prior to 2018, cases of paratyphoid fever were included with salmonellosis cases in Table 2.
• With the removal of paratyphoid fever cases from the salmonellosis case counts in 2018, salmonellosis was replaced with "salmonellosis (excluding paratyphoid fever and typhoid fever)" in Table 2. To obtain data that are comparable to previous years (2017 and earlier), you will need to sum the paratyphoid case count with the "salmonellosis (excluding paratyphoid fever and typhoid fever)" cases count.
• Carbapenemase Producing Carbapenem-Resistant Enterobacteriaceae (CP-CRE), due to Klebsiella spp, Escherichia coli, and Enterobacter spp. were added to Table 2.

Errata

February 2019

Weeks 1-52 data for Haemophilus influenzae, invasive disease in Table 1 of the 2018 data were updated on Monday, February 11, 2019. Labels for "Nontypeable" and "Non-b serotype" were incorrectly placed resulting in the numbers being switched for these two rows. They are now correct.

Notices

June 2025

The following changes have been made to the 2023 annual tables based on the approved 2022 Council of State and Territorial Epidemiologists (CSTE) position statements:

• Animal rabies
  • Beginning in 2023, animal rabies confirmed case classifications were published to align with the approved CSTE position statement 22-ID-06.
• Candida auris clinical
  • Beginning in 2023, confirmed cases of Candida auris clinical are published to align with the approved CSTE position statement 22-ID-05, whereas in previous years, confirmed and probable case classification statuses were published.
• Candida auris screening
  • Beginning in 2023, Candida auris screening was added as a nationally notifiable condition, and confirmed cases are published to align with the approved CSTE position statement 22-ID-05.
• Carbapenemase-producing organisms (CPO), clinical and CPO, screening
  • Beginning in 2023, cases began to be reported as carbapenemase-producing organisms, clinical or carbapenemase-producing organisms, screening. In previous years, only carbapenemase-producing carbapenem-resistant Enterobacteriaceae (CP-CRE) cases were reported. Additionally, CPO total is the sum of CP-CRE cases reported in MMWR year 2023, CPO, clinical cases, and CPO, screening cases.
• Coronavirus disease 2019 (COVID-19)
  • Beginning in 2023, confirmed and probable cases of COVID-19 are published to align with the approved CSTE position statement 22-ID-01.
• Coccidioidomycosis
  • Beginning in 2023, for surveillance reporting purposes, jurisdictions are grouped into high- and low-incidence categories. Probable cases are only reported from low-incidence jurisdictions, while confirmed cases are reported from both high- and low-incidence jurisdictions.
• Gonorrhea
  • Beginning in 2023, confirmed and probable cases of gonorrhea are published to align with the approved CSTE position statement 22-ID-03, whereas in previous years, all case classification statuses were published. This change may cause a decrease in published case counts when compared to previous years.
• Melioidosis
  • Beginning in 2023, melioidosis was added as a nationally notifiable condition. Confirmed and probable cases are published to align with the approved CSTE position statement 22-ID-08.

Refer to the NNDSS case definition website for new and revised surveillance case definitions. The Council of State and Territorial Epidemiologists (CSTE) approved revised 2023 case definitions for animal rabies, candida auris clinical and screening, carbapenemase-producing organisms clinical and screening, coccidioidomycosis, COVID-19, gonorrhea, and melioidosis. The full CSTE position statements can be found on the CSTE position statement archive website.

Additional changes or notices for the 2023 annual tables:

• Beginning in 2023, varicella mortality will have an age restriction of <50 years applied to the numerator (i.e., case counts). This is based on updates to CDC processes for validating varicella mortality cases.
• Connecticut identified an issue that prevented the correct assignment of ethnicity values in case notifications to the CDC for the 2023 NNDSS annual tables, specifically affecting case counts for sexually transmitted diseases, including chancroid, Chlamydia trachomatis infection, gonorrhea, and all stages of syphilis, which were re-assigned to 'Ethnicity not stated' in Table 7.
• Delaware identified an issue that prevented the correct assignment of ethnicity values within their surveillance system for certain conditions included in the 2023 NNDSS annual tables. As a result, case counts for chronic hepatitis B virus infection, Haemophilus influenzae, varicella morbidity, and invasive pneumococcal disease were re-assigned to 'Ethnicity not stated' in Table 7. No other conditions were affected.
• Delaware was unable to provide race and ethnicity data for COVID-19 cases; therefore, these cases have been categorized as 'Race not stated' and 'Ethnicity not stated' in Tables 6 and 7.
• New Mexico designated E. chaffeensis and A. phagocytophilum as reportable diseases in 2023. However, this change is not reflected in the 2023 NNDSS annual tables, where these conditions are still marked with an 'N' and interpreted as 'Not Reportable.'

Notices

August 2024

Disease data presented in the 2022 tables reflect impacts of the COVID-19 pandemic, such as changes in exposure-related behavior, healthcare-seeking behavior, disease reporting, and public health investigations.

Changes to the 2022 annual tables as a result of approved 2021 Council of State and Territorial Epidemiologists position statements include the following:

• Chapare virus
  • Beginning in January 2022, Chapare virus was added as a nationally notifiable condition and confirmed and suspect cases combined are published to align with the approved CSTE position statement 21-ID-04.
• Chlamydia
  • Only confirmed cases are published to align with the approved CSTE position statement 21-ID-06, whereas in previous years, all case classification statuses were published. This change may cause a decrease in published case counts when compared to previous years.
• Lyme
  • For surveillance reporting purposes, jurisdictions are grouped into high- and low-incidence categories. Confirmed cases are only reported from low-incidence jurisdictions; however, probable cases are reported from both high- and low-incidence jurisdictions. For more information on jurisdiction classifications, visit https://www.cdc.gov/lyme. Currently, high-incidence jurisdictions include Connecticut, Delaware, Maine, Maryland, Massachusetts, Minnesota, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, Virginia, West Virginia, Wisconsin, and the District of Columbia.
• Viral hemorrhagic fevers
  • Beginning in January 2022, confirmed and suspect cases combined are published to align with the approved CSTE position statement 21-ID-04, whereas in previous years, only confirmed cases were published.
    

Changes to the 2022 annual tables as a result of approved 2022 Council of State and Territorial Epidemiologists position statements include the following:

• Monkeypox
  • CSTE adopted Monkeypox as a nationally notifiable condition on June 23, 2022 and beginning August 1, 2022 confirmed and probable cases are published to align with the CSTE position statement 22-ID-10. Case classifications for cases reported prior to August 1, 2022 should not have been retroactively changed based on the case definition in the CSTE position statement 22-ID-10.

The following footnote was added to the ethnicity (Table 7) table:

• Delaware identified an issue preventing the correct assignment of ethnicity values within their surveillance system for a portion of the conditions included in the 2022 NNDSS annual tables. Cases of hepatitis, human immunodeficiency virus diagnoses, sexually transmitted diseases, and tuberculosis were not impacted, but Delaware's case counts for all other conditions were re-assigned to 'Ethnicity not stated' in Table 7.

Beginning in 2022, rates for perinatal hepatitis B infection and perinatal hepatitis C infection will not be calculated. This is due to population estimates not being available for the specific sub-populations required to align with the defined age restriction criteria of the case definition.

Notices

January 2024

Disease data presented in the 2021 tables reflect impacts of the COVID-19 pandemic, such as changes in exposure-related behavior, healthcare-seeking behavior, disease reporting, and public health investigations.

• CSTE adopted the first 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. On June 17, 2021, a revision to the COVID-19 national surveillance case definition was approved, effective September 1, 2021.

Notices

January 2023

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.

The following changes were made to the annual 2020 tables of nationally notifiable infectious diseases and conditions:

• Beginning in the 2020 annual tables, reported cases among non-U.S. residents are displayed in a separate row in Table 2. Based on the country of usual residence (COUR) algorithm, 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. Data in Table 2 are stratified into the following four categories based upon the COUR algorithm: U.S. Residents, excluding U.S. Territories; U.S. Territories; Non-U.S. Residents; and Total.
• Beginning in the 2020 annual tables, the following footnote was added to the race (Table 6) and ethnicity (Table 7) tables:
  • Any variation of disease incidence by race or ethnicity does not reflect biological differences but reflects systemic, cultural, behavioral, and social factors including structural racism.
• Beginning in the 2020 annual tables, the following category changes were made to the race table (Table 6) to align with OMB standards: "Black" changed to "Black or African American," and "Other Race" changed to "Other or Multi-Race" to account for individuals reported as other race or multiple races.
• Beginning in the 2020 annual tables, the footnote for "Total, all stages" was modified to include congenital syphilis, which was mistakenly omitted in the footnotes in 2018 and 2019 annual tables.
• 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.
• 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.
• As a result of position statements the Council of State and Territorial Epidemiologists (CSTE) approved in 2019, case definition revisions were implemented by jurisdictions in 2020 for the following conditions: acute and chronic hepatitis C, legionellosis, pertussis, plague, and spotted fever rickettsiosis. Chronic hepatitis C data are published online by the CDC's Division of Viral Hepatitis available at Viral Hepatitis Surveillance Reports | Viral Hepatitis | CDC.
• Changes to the 2020 annual tables as a result of approved 2019 CSTE position statements, include the following:
  • Confirmed and probable cases of plague are combined and published in the 2020 annual tables whereas only confirmed cases were published in the 2019 tables.
  • Beginning in 2020, legionellosis cases diagnosed by PCR were classified as confirmed, whereas previously those cases were classified as suspect and did not meet the publication/print criteria.
• Changes to the 2020 annual tables as a result of approved 2020 Council of State and Territorial Epidemiologists position statements include the following:
  • CSTE adopted the first 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. Confirmed and probable cases are published in the 2020 annual tables.
• In 2021, the NNDSS web site moved. This change impacts where to find supporting documentation and the citation in previously published tables. Specifically, the links have changed for the following resources:
  • NNDSS: now available at About National Notifiable Diseases Surveillance System | National Notifiable Diseases Surveillance System (NNDSS) | CDC
  • Infectious tables - see Using and Interpreting Data: now available at this page.
  • Readers' Guides: now available at NNDSS Readers' Guides | National Notifiable Diseases Surveillance System (NNDSS) | CDC
  • Technical Resource Center: now available at
    Technical Resource Center | National Notifiable Diseases Surveillance System (NNDSS) | CDC
  • Surveillance Case Definitions: now available at Surveillance Case Definitions for Current and Historical Conditions
  • MMWR Weeks Fact Sheet: now available at MMWR Week Fact Sheet
  • MMWR Weeks Calendar: now available at Event Codes & Other Surveillance Resources

Notices

May 2021

The following changes were made to the annual 2019 tables of nationally notifiable infectious diseases and conditions:

• The 2019 annual tables exclude cases of nationally notifiable conditions and diseases among non-U.S. residents. As a result, Table 2 does not include a "Non-U.S. Resident" or "Total" row, that would have been included in the table had the data been stratified into the following four categories, based upon the "country of usual residence" (COUR) algorithm: U.S. Residents, excluding U.S. Territories; U.S. Territories; Non-US. Residents; and Total. Table 2 for the 2019 annual tables only includes the first two of these stratification categories.
• The following 24 jurisdictions may have incomplete data, due to the coronavirus disease 2019 (COVID-19) pandemic: Alaska, California, Connecticut, Delaware, District of Columbia, Florida, Idaho, Indiana, Kansas, Massachusetts, Minnesota, Missouri, Montana, Nebraska, New Hampshire, New York State (excluding New York City), New York City, North Dakota, Ohio, Oklahoma, South Carolina, Tennessee, Texas, and West Virginia. In addition, the following 2 U.S. Territories may have incomplete data due to the COVID-19 pandemic: American Samoa and the U.S. Virgin Islands.
• As a result of position statements the Council of State and Territorial Epidemiologists (CSTE) approved in 2018, case definition revisions were implemented in 2019 for the following conditions: acute hepatitis A; Candida auris, clinical; diphtheria; Salmonella Typhi infection; Salmonella Paratyphi infection; listeriosis; and yellow fever.
• Changes to the 2019 annual tables as a result of approved 2018 CSTE position statements include the following:
  • Candida auris, clinical was added as a new nationally notifiable disease.
  • Salmonella Paratyphi infection and Salmonella Typhi infection replaced Paratyphoid fever and Typhoid fever, respectively.
  • Salmonellosis (excluding S. Typhi infection and S. Paratyphi infection) replaced Salmonellosis (excluding paratyphoid fever and typhoid fever).
  • Carbapenemase-producing carbapenem-resistant Enterobacteriaceae (CP-CRE) represents a consolidation of CP-CRE species Klebsiella spp, CP-CRE E. coli, and CP-CRE Enterobacter spp.
  • Confirmed cases of diphtheria are published in the 2019 annual tables whereas confirmed, probable and unknown cases were published in the 2018 tables.
  • Beginning in 2019, confirmed and probable cases of listeriosis are being reported and displayed in the annual tables, and maternal and neonatal cases are being counted separately. Before 2019, probable cases were not reported, and cases in neonates ≤60 days of age were counted as one case in a mother-infant pair.