Preliminary 2021 STD Surveillance Data

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Sexually Transmitted Disease Surveillance: Preliminary 2021 Data presents trends in nationally notifiable sexually transmitted diseases (STDs) in the United States based on preliminary 2021 data and intended as a reference document for policy makers, program managers, health planners, researchers, and others who are concerned with the public health implications of these diseases.

As the COVID-19 pandemic continues to cause reporting delays, the preliminary 2021 data reflect data provided to CDC through the National Notifiable Diseases Surveillance System (NNDSS) as of July 7, 2022, through the STD Surveillance Network (SSuN) as of June 15, 2022, and through the Gonococcal Isolate Surveillance Project (GISP) as of June 23, 2022. These data are considered preliminary as STD surveillance data collected during 2021 will continue to be provided to CDC through fall of 2022. Final 2021 data, including STD case counts and rates for states and territories, will be included in the 2021 STD Surveillance Report when it is released in 2023.

During 2021, the COVID-19 pandemic continued to impact trends in diagnosed and reported STDs, as well as in data collected through enhanced and sentinel STD surveillance activities; therefore, the STD data presented in this report for the years 2020 and 2021 should be interpreted with caution. For more information, see Impact of COVID-19 on STDs.

The data and methodology used in this preliminary report are similar to those used for the 2020 STD Surveillance Report. See the STD Surveillance Report 2020: Technical Notes for a full description of data sources and methodology.  

The following details are specific for the the 2021 preliminary STD case data collected through NNDSS:

• NNDSS STD case notification data presented in this report are compiled from electronic data received through the National Electronic Telecommunications System for Surveillance (NETSS) and via Health level 7 (HL7) messaging using National Electronic Disease Surveillance System (NEDSS) standards. Additionally, select jurisdictions provide congenital syphilis cases via REDCap. In 2021, nine jurisdictions (Alabama, Connecticut, Idaho, Kentucky, Michigan, North Carolina, Oregon, South Carolina, and Wisconsin) provided STD case notification data to CDC via HL7 messaging. In 2021, 34 states provided congenital syphilis data through REDCap.
• Denominators for rates of reported cases of STDs, excluding congenital syphilis, use population estimates from the United States Census Bureau. For figures presenting race using the 1997 Office of Management and Budget standards, non-bridged-race data are used. The most recently available population estimates at time of publication are used, with case rates for 2021 calculated using 2021 population estimates. Because of the use of the updated population data, case rates for 2000–2020 may be different from those presented in previous STD surveillance reports.
• Congenital syphilis rates were calculated by using live birth data provided to National Center for Health Statistics through the Vital Statistics Cooperative Program. The most recently available data at time of publication are used, with case rates for 2020 and 2021 calculated using 2020 live birth data. Because of the use of the updated population data, case rates for 2000–2020 may be different from those presented in previous STD surveillance reports.