Data Methods
Learn more about the data that informs AHEAD.
Data Methods
Diagnoses
HIV diagnoses refers to the number of people who have received an HIV diagnosis during a given time period, regardless of when they became HIV+. Some people may live with HIV for years before they are actually diagnosed, while others are diagnosed soon after acquiring HIV. The baseline value of the HIV diagnoses indicator was calculated using National HIV Surveillance System (NHSS) data from January 1, 2017 through December 31, 2017 and reported to CDC through December 31, 2019. Number of reported HIV infections among persons aged ≥13 years that were confirmed through laboratory or clinical evidence during a calendar year. Diagnosis data is based on residence at the time of diagnosis and is updated quarterly. Data presented by quarter: Presentation of diagnoses data for a quarter includes cumulative counts of HIV diagnoses through the specified quarter of the calendar year. Data presented by quarter are preliminary.

Data for the year 2020 should be interpreted with caution due to the impact of the COVID-19 pandemic on access to HIV testing, care-related services, and HIV case surveillance activities in state/local jurisdictions. Inclusion of 2020 data in trend assessments is discouraged. The reduction in HIV diagnoses in 2020 is likely due to disruptions in clinical care services, patient hesitancy in accessing clinical services, and shortages in HIV testing reagents/materials during the COVID-19 pandemic.
Data for years 2021 and 2022 are considered preliminary and based on data reported to CDC’s National HIV Surveillance System as of March 2022. Diagnoses data are preliminary through March 2022.
Due to the impact of the COVID-19 pandemic, data for the year 2020 should be interpreted with caution. COVID-19 disruptions in HIV, diagnosis, care and reporting of deaths during 2020 have also made incidence, prevalence, and knowledge of status estimates derived from a CD4-based model, unreliable. Therefore, the HIV surveillance supplemental report Estimated HIV Incidence and Prevalence in the U.S., which provides data on estimated incidence, prevalence, and knowledge of status in the U.S., was not published by CDC this year.
Data reported to the NHSS are considered preliminary until a 12-month reporting delay has been reached.
More information about Diagnoses data can be found at: HIV Surveillance Report 2020, Volume 33.
The most recent CDC Diagnoses data can be found at: HIV Surveillance Data Tables 2022, Vol. 3, No. 2.