Data Methods

Learn more about the data that informs AHEAD.

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PrEP Coverage indicator icon PrEP Coverage

Reported as a percentage, PrEP coverage was calculated as the number of persons aged ≥16 years classified as having been prescribed PrEP divided by the estimated number of persons who had indications for PrEP. PrEP prescription data values <40 in any jurisdiction are not reported because of reliability concerns. PrEP coverage data for 2018 have been updated using a 2018 denominator for the estimated number of persons with PrEP indications.

Caution should be used when interpreting the PrEP coverage percentages. Different data sources were used for the numerator and denominator; therefore, it is unknown whether all persons prescribed PrEP (numerator) are also contained in the estimate of the number of persons with indications for PrEP (denominator).

The number of persons aged ≥16 years classified as having been prescribed PrEP was calculated using national pharmacy data from the IQVIA Real World Data–Longitudinal Prescriptions database. The annual number of persons aged ≥16 years classified as having been prescribed PrEP prescriptions was determined using a validated algorithm that included persons who had at least one tenofovir disoproxil fumarate and emtricitabine (TDF/FTC) prescription for >28 days and for whom TDF/FTC was not prescribed for HIV treatment, hepatitis B treatment, or HIV postexposure prophylaxis. Although IQVIA recorded 92% of all prescriptions from retail pharmacies in the United States, prescriptions from closed health care systems that do not make their prescription data available to IQVIA (e.g., managed care organizations or military health plans) were not included. Therefore, the calculated values represent minimum estimates of PrEP coverage. PrEP coverage is not available by transmission category due to lack of availability in the IQVIA database.

Please use caution when interpreting PrEP data by race/ethnicity. Race/ethnicity categories available in the IQVIA data include white, black/African American, Hispanic/Latinx, and other. The number of persons prescribed PrEP for each racial/ethnic group presented was extrapolated by applying the racial/ethnic distribution of known records to those for which data on race/ethnicity were unknown.

To estimate the number of persons prescribed PrEP at the state or county level, a probability-based approach is used to crosswalk between a 3-digit zip code assigned by the U.S. Postal Service and states or counties. Because of reliability concerns, subnational estimates of <40 are not reported.

For more information on the methods for estimating the number of persons prescribed PrEP, please refer to the following published reports:

  1. Huang YA, Zhu W, Smith DK, Harris N, Hoover KW. HIV Preexposure Prophylaxis, by Race and Ethnicity — United States, 2014–2016. MMWR Morb Mortal Wkly Rep 2018;67:1147–1150. DOI: http://dx.doi.org/10.15585/mmwr.mm6741a3external icon.
  2. Smith DK, Van Handel M, Grey J. Estimates of adults with indications for HIV pre-exposure prophylaxis by jurisdiction, transmission risk group, and race/ethnicity, United States, 2015. Ann Epidemiol 2018 Dec;28(12):850-857
  3. Harris NS, Johnson AS, Huang YA, et al. Vital Signs: Status of Human Immunodeficiency Virus Testing, Viral Suppression, and HIV Preexposure Prophylaxis — United States, 2013–2018. MMWR Morb Mortal Wkly Rep 2019;68:1117–1123. DOI: http://dx.doi.org/10.15585/mmwr.mm6848e1external icon
  4. Furukawa NW, Smith DK, Gonzalez CJ, et al. Evaluation of Algorithms Used for PrEP Surveillance Using a Reference Population From New York City, July 2016–June 2018. Public Health Reports 2020; 135(2): 202-210.

The number of persons aged ≥16 years with indications for PrEP was estimated using most recently available data from U.S. Census American Community Survey (ACS), the National Health and Nutrition Examination Survey (NHANES), and National HIV Surveillance System (NHSS). The data sources used in calculating the denominator for PrEP coverage have varying dates for schedule of availability for the latest data. Therefore, denominator data used for PrEP coverage lags approximately 1 year after the year of report. PrEP coverage data with a lagged denominator were considered preliminary.

ACS and U.S. Census Bureau datasets, which include household data on cohabitating same-sex partners, were used to estimate the number of men who have sex with men (MSM) in a jurisdiction. Next, behavioral data from NHANES were used to estimate the proportion of HIV-negative MSM with indications for PrEP. Finally, the number of HIV-negative MSM with indications for PrEP was multiplied by the ratio of percentage of HIV diagnoses (from NHSS) during the specified year attributed to other major transmission risk groups compared to the percentage among MSM in a given state or county. The estimated number of persons with indications for PrEP in the 3 major transmission risk groups (MSM, heterosexuals, persons who inject drugs) in each jurisdiction was then summed to yield a state- or county-specific estimate. State estimates were then summed for a national total of persons with indications for PrEP. For further details, please refer to the report below.

For all states and jurisdictions except Puerto Rico, 2017 data from all sources were used in calculating both the numerator and denominator of the 2017 PrEP coverage estimate. The number of MSM in a jurisdiction is determined using the American Community Survey (ACS) of the US Census, and the ACS is one of the 3 data sources used to estimate the number of persons with indications for PrEP (PrEP coverage denominator). However, prior to 2018, ACS did not include data needed to estimate the number of persons with indications for PrEP in Puerto Rico; consequently, the number of persons with indications for PrEP in Puerto Rico in 2017, was not available. In 2018, the ACS conducted a separate Puerto Rico survey and these data are now available and are being used to determine the number of persons with indications for PrEP in 2018 for Puerto Rico. In addition, 2017 PrEP coverage for Puerto Rico is now provided using the 2018 denominator for Puerto Rico. PrEP coverage for San Juan is not displayed due to reliability concerns.

For more information on the methods for estimating the number of persons with indications for PrEP, please refer to the following published reports:

  1. Centers for Disease Control and Prevention. HIV Surveillance Data Tables (early release): Core indicators for monitoring the Ending the HIV Epidemic initiative, data reported through December 2019. https://www.cdc.gov/hiv/pdf/library/reports/ehe-core-indicators/cdc-hiv-ehe-core-indicators-2019.pdf. Published March 2020. Accessed May 26, 2020.
  2. Grey JA, Bernstein KT, Sullivan PS, Purcell DW, Chesson HW, Gift TL, et al. Estimating the population sizes of men who have sex with men in US states and counties using data from the American Community Survey. JMIR Public Health Surveill 2016;2(1):e14
  3. CDC [Smith DK, Van Handel M, Wolitski RJ, et al]. Vital Signs: Estimated percentages and numbers of adults with indications for preexposure prophylaxis to prevent HIV acquisition—United States, 2015. MMWR 2015;64(46):1291–1295. doi:10.15585/ mmwr.mm6446a4.
  4. Smith DK, Van Handel M, Grey J. Estimates of adults with indications for HIV pre-exposure prophylaxis by jurisdiction, transmission risk group, and race/ethnicity, United States, 2015. Ann Epidemiol 2018;28(12):850– 857.e9. doi:10.1016/j.annepidem.2018.05.003.”