Additional Information

Data Source Notes

Aggregate COVID-19 Case and Death Surveillance Data: Based on aggregate counts reported by state and territorial jurisdictions to CDC since January 21, 2020. Data are reported weekly and data from previous weeks may be updated. Data reported through November 9, 2022, were used in this report. CDC uses various methods to gather aggregate case and death data from states, territories, and other jurisdictions’ health departments. The methods and frequency of data reporting vary by jurisdiction. The dates used to document case and death incidence also vary. For additional information, see: About CDC Case and Death COVID-19 Data.

Coronavirus Disease 2019 (COVID-19)-Associated Hospitalization Surveillance Network (COVID-Net): COVID-NET is a population-based surveillance system that collects data on laboratory-confirmed COVID-19-associated hospitalizations among children and adults. The current network is comprised of over 300 acute-care hospitals in 13 states. COVID-NET coverage comprises 98 counties in the 13 states participating in the Emerging Infections Program (EIP) and the Influenza Hospitalization Surveillance Project (IHSP). COVID-NET covers approximately 10 percent of the U.S. population. The designated COVID-NET surveillance area is generally similar to the U.S. population by demographics; however, the information might not be generalizable to the entire country. Data reported through August 31, 2022, were used in this report. For additional information, see: Coronavirus Disease 2019 (COVID-19)-Associated Hospitalization Surveillance Network (COVID-NET) | CDC and CDC COVID Data Tracker: About Health Care Setting Data.

Linked Case Surveillance, Immunization Registry and Vital Registration Data: To monitor rates of COVID-19 cases and deaths by vaccination status, data are reported from jurisdictions that can link case surveillance data to immunization registries and vital registration records. The participating jurisdictions represent over 70% of the U.S. population and all regions of the country. Monitoring COVID-19 rates by vaccination status can indicate changes in vaccine effectiveness that can be confirmed through robust, controlled studies. Data posted on October 21, 2022 on COVID-19 associated deaths in COVID-19 cases diagnosed through September 3, 2022, were used in this report.  A 5-week reporting lag time for deaths allows for more complete reporting, data linkage, and mortality ascertainment. For additional information, see: COVID-19 Vaccine Breakthrough Case Investigation and Reporting and COVID Data Tracker, Rates of COVID-19 Cases and Deaths by Vaccination Status.

National Patient-Centered Clinical Research Network (PCORnet): PCORnet is comprised of 60 network partners embedded within 9 clinical research networks. Data are derived from electronic medical records from up to 42 healthcare systems and 1 health plan participating in a CDC-funded COVID-19 surveillance project. Data from this surveillance system are not nationally representative. Data reported through July 31, 2022, were used in this report. For additional information, see: https://pcornet.org/data/ and CDC COVID Data Tracker: About Health Care Setting Data.

Premier Healthcare Database Special COVID-19 release: Data are from 678 hospitals that continuously contributed at least one inpatient record per month during April 2020–May 2022. Data reported as of August 2, 2022 for hospitalizations occurring through June 30, 2022, were used in this report. For additional information, see: Premier Healthcare Database Special COVID-19 Release and CDC COVID Data Tracker: About Health Care Setting Data.

Provisional Death Counts for COVID-19, National Center for Health Statistics. National Vital Statistics System.: Provisional mortality estimates from 2021 and 2022 are based on all complete death records received and processed by the CDC’s National Center for Health Statistics (NCHS) as of a specified cutoff date. National provisional estimates include events occurring only within the 50 U.S states and the District of Columbia. NCHS receives the death records and monthly provisional occurrence counts from state vital registration systems through the Vital Statistics Cooperative Program. Provisional death counts might not match counts from other sources, such as media reports or numbers from county health departments. Counts by NCHS often track 1–2 weeks behind other data and States report at different rates. Provisional counts are not final and are subject to change. Counts from previous weeks are continually revised as more records are received and processed. Data reported through September 30, 2022, were used in this report. Provisional “Multiple Cause of Death, Current Final Multiple Cause of Death Data” can be accessed at Multiple Cause of Death Data on CDC WONDER. For additional information, see: https://www.cdc.gov/nchs/covid19/mortality-overview.htm and https://www.cdc.gov/nchs/nvss/vsrr/covid19/tech_notes.htm

Unified Hospital Dataset: Includes data reported by hospitals registered with the Centers for Medicare & Medicaid Services (CMS) as of June 1, 2020 and data from non-CMS hospitals since July 15, 2020. Data, including counts of new hospital admissions of patients with confirmed COVID-19 by age group, are reported either directly from facilities or via state submissions. Data reported through November 9, 2022, were used in this report. For additional information, see: https://www.hhs.gov/sites/default/files/covid-19-faqs-hospitals-hospital-laboratory-acute-care-facility-data-reporting.pdf and CDC COVID Data Tracker: About Health Care Setting Data.

Vaccine Administration Data: Vaccine administration data are reported to the U.S. Department of Health and Human Services (HHS) and CDC by jurisdictional and federal partners via immunization information systems, the Vaccine Administration Management System, or direct data submission and can be accessed via CDC COVID Data Tracker: Vaccination Delivery and Coverage.  Data are cumulative counts of individual COVID-19 vaccine doses administered since December 14, 2020. Vaccine administration data reported through June 29, 2022 were used for this report. Note that the linked case surveillance, immunization registry and vital registration data used in this report, which is a separate data source but which uses jurisdictional-level immunization data, included linked vaccine administration data reported through September 3, 2022.

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Acknowledgements

Authors of and contributors to this report are members of CDC’s COVID-19 Response Team.