Data Methods
Learn more about the data that informs AHEAD.
Data Methods
PrEP Coverage
PrEP coverage, reported as a percentage, was calculated as the number who have 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. For more detailed information on the denominator of this indicator, please visit the CDC Data Tables. The data sources used to estimate the number of persons with indications for PrEP have different schedules of availability. Therefore, the availability of a denominator year might lag the availability of a numerator year by 1 or more years.
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 prescribed PrEP was estimated using data from IQVIA pharmacy database reported through December 2021 based on an algorithm that included FDA approved drugs for PrEP. The validated algorithm 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.
- Tenofovir alafenamide and emtricitabine (TAF/FTC) was approved as an alternative drug for PrEP by the U.S. Food and Drug Administration in October 2019. Starting in 2019, TAF/FTC was included in the algorithm.
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 the lack of availability in the IQVIA database.
Race/ethnicity data were only available for <40% of persons prescribed PrEP each year. Number prescribed PrEP and PrEP coverage by race/ethnicity were adjusted applying the distribution of records with known race/ethnicity to records with missing race/ethnicity. Hispanic/Latino persons can be of any race. Race/ethnicity categories available in the IQVIA data include:
- Black/African American,
- Hispanic/Latino,
- Other, and
- White.
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.
The number of persons with PrEP indications was estimated using 2018 data from National HIV Surveillance System, data from the National Health and Nutrition Examination Survey, and from U.S. Census Bureau’s American Community Survey. Data are rounded to the nearest 10. Data for which values are unknown were not reported thus values may not sum to column total. The data sources used to estimate the number of persons with indications for PrEP have different schedules of data availability. Consequently, the availability of a denominator may lag the availability of a numerator. 2017 denominators were used for 2017 PrEP coverage data; 2018 denominators were used for 2018, 2019, 2020 and 2021 PrEP coverage data; consequently, 2019-2021 PrEP coverage data are 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 groups at highest risk of transmission (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 and the San Juan Municipio; 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. The number of persons with PrEP indications in Puerto Rico and the San Juan Municipio are not available for 2017. 2018 data are used for 2017.
Data for the years 2020 and 2021 are preliminary and should be interpreted with awareness of the impact of the COVID-19 pandemic on filling PrEP prescriptions in state/local jurisdictions.
For more information on the methods for estimating the number of persons prescribed PrEP, please refer to the following published reports:
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.
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.
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.
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
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.mm6848e1
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.mm6741a3
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.
More information about PrEP Coverage data can be found at: HIV Surveillance Report Supplemental Report Volume 27, Number 3
The most recent CDC PrEP Coverage data can be found at: HIV Surveillance Data Tables 2022, Vol. 3, No. 2