Glossary

Age and Age Groups

Data for all indicators include persons aged ≥13 years except PrEP estimates which are for persons ≥16 years as these numbers are calculated using national pharmacy data from the IQVIA Real World Data–Longitudinal Prescriptions database (and not NHSS, which includes persons ≥13 years). These data are grouped into ten-year age groups. Age groups (rather than single year of age) are used to ensure data security and confidentiality.

AIDS

“AIDS” stands for Acquired immunodeficiency syndrome. It is the most severe phase of HIV infection. People with HIV classified as stage 3 AIDS have such badly damaged immune systems that they get an increasing number of severe illnesses, called opportunistic illnesses. Without treatment, people with HIV classified as stage 3 (AIDS) typically survive about 3 years. Common symptoms of stage 3 (AIDS) include chills, fever, sweats, swollen lymph glands, weakness, and weight loss. People are classified as stage 3 (AIDS) when their CD4 cell count drops below 200 cells/mm or if they develop certain opportunistic illnesses. People with HIV classified as stage 3 (AIDS) can have a high viral load and be very infectious (also see: HIV).

Antiretroviral Therapy (ART)

The treatment for persons living with HIV. ART involves taking a combination of HIV medicines (called an HIV treatment regimen) every day. ART reduces the amount of virus in the body.

Baseline Data

Baseline data are the initial data collected prior to the start of an intervention. These data serve as a point of reference as subsequent data are collected and compared against the baseline data to measure progress towards intervention goals. AHEAD uses data from 2017 as the baseline.

Cases

Cases refers to the number of new cases of disease in a defined population over a specific time period.

CD4 Depletion Model

Model that enables the use of an estimate for a subject-specific expected time to cross a CD4 threshold and to estimate a subject-specific probability to have CD4 count above a pre-specified threshold at each time point. When a person with HIV has received no treatment, the CD4 cell count can be used to estimate the time since infection at the date of CD4 test.

Confidence Interval (CI)

These represent the range in which the population value is likely to be. They are computed using the estimate of the population value and the associated standard error.

Cumulative Quarterly Data

Data presented cumulatively by quarter are always preliminary and are presented for a data year. For example, Q2 2020 data include Q1 2020 and Q2 2020. Cumulative quarterly data provide the most timely data available.

Diagnoses

On this site, HIV diagnoses refer to the number of people with HIV diagnosed in a given year by laboratory or clinical evidence. This does not include persons with infections that have not yet been diagnosed.

Gender

On this site, the term gender refers to a person’s internal understanding of his or her gender, or the gender with which a person identifies – and includes the following categories: male, female, transgender woman, transgender man, and additional gender identity (e.g., bigender, gender queer, two-spirit).

Geography

This site contains data at the national-, state-, and county- level. Data at the state- or county- level may be suppressed to protect against a situation in which a person could potentially be identified (e.g., a small number of cases). Puerto Rico is a territory included at the state-level. Washington, DC and San Juan, PR are areas included with the county-level.

HIV diagnoses data by jurisdiction are based on residence at time of diagnosis of HIV infection.

Linkage to care data by jurisdiction are based on residence at time of diagnosis of HIV infection.

Viral suppression data by jurisdiction are based on most recent known address at the end of the specified year.

HIV

"HIV" stands for human immunodeficiency virus. It is the virus that can lead to acquired immunodeficiency syndrome or AIDS if not treated. Unlike some other viruses, the human body can’t get rid of HIV completely, even with treatment. So once you get HIV, you have it for life. HIV attacks the body’s immune system, specifically the CD4 cells (T cells), which help the immune system fight off infections. Untreated, HIV reduces the number of CD4 cells (T cells) in the body, making the person more likely to get other infections or infection-related cancers. Over time, HIV can destroy so many of these cells that the body can’t fight off infections and disease. These opportunistic infections or cancers take advantage of a very weak immune system and signal that the person has AIDS, the last stage of HIV infection.

Incidence

HIV incidence is the estimated number of persons who became newly infected with HIV in a given year, whether or not their infection has been diagnosed.

Knowledge of Status

Knowledge (or awareness) of HIV-positive status occurs when a person with HIV is tested and receives a diagnosis of HIV infection. Getting tested and knowing one’s HIV serostatus are entry points for an individual to receive either HIV prevention services (if HIV negative) or HIV medical care (if HIV positive), both of which are important to staying healthy and limiting the spread of HIV.

Linkage to care

Linkage to care refers to having accessed medical care for HIV infection after receiving a diagnosis. This is a crucial early step in successful HIV treatment because this enables a person with HIV infection to see a medical provider who can check the person’s health and prescribe the antiretroviral therapy needed for viral suppression. The more quickly individuals with HIV can be linked into medical care after receiving a diagnosis, the greater the impact medical care can have in keeping them healthy and in limiting the spread of HIV, through viral suppression.

MSM

Persons whose transmission category is classified as male-to-male sexual contact include men who report sexual contact with other men (i.e., homosexual contact) and men who report sexual contact with both men and women (i.e., bisexual contact).

Preliminary Data

Preliminary data are data that do not have 12 months of reporting delay and can apply to both annual and cumulative quarterly data. For example, 2022 annual data using a December 2022 dataset are preliminary. For PrEP coverage, data are considered preliminary if a denominator year lag a numerator year.

PrEP

Pre-exposure prophylaxis (or PrEP) is oral or injectable medicine that people at very high risk for HIV can take to prevent HIV. PrEP medications can stop HIV from taking hold and spreading throughout your body. When taken as recommended, PrEP medication is highly effective for preventing HIV from sex or injection drug use. PrEP is much less effective when it is not taken consistently.

Prevalence

The number of diagnosed disease cases in a defined population during a specific time period.

Provisional Data

Provisional data are data that have at least 12 months of reporting delay and applies only to annual data. For example, 2021 annual data using a December 2022 dataset are provisional.

Race / Ethnicity

Data are generally grouped into the following racial/ethnic categories (each race category is non-Hispanic): American Indian or Alaska Native, Asian, Black or African American, Hispanic/Latino, Native Hawaiian or other Pacific Islander, White and multiracial. Hispanic/Latino persons can be of any race.

PrEP data has different race/ethnicity categories due to the source of the data. The categories for PrEP are: Black/African American, Hispanic/Latino, Other, and White.

Some HIV prevalence cases are missing information on the individual’s race/ethnicity. These unknown racial/ethnic groups are not displayed. Therefore, if you summarize the data by race/ethnicity, they may not match the national totals overall.

Relative Standard Error (RSE)

When the value of an indicator was estimated rather than measured directly, there is always possible error in the estimation based on variation that can occur by chance. This is called a standard error, and it is a measurement of the likely difference between the estimated value and the true value (directly measured value) for the population. Lower percentages are considered more reliable for general use.

Relative standard errors (RSEs) were calculated for estimates of incidence, prevalence, and percentages of persons living with diagnosed HIV infection and were used to determine the reliability of estimates. Estimates with a RSE of < 30% meet the standard of reliability and are displayed. Estimates with a RSE of 30%–50% meet a lower standard of reliability and are displayed but should be interpreted with caution. Estimates with a RSE of > 50% are statistically unreliable and not displayed.

On this site, estimates of the indicators HIV incidence and knowledge of status with a relative standard error (RSE) of ≥30% are represented in the following way:

• Estimates with an RSE of 30%-50% are marked with an asterisk "*", indicating they should be used with caution.
• Estimates with an RSE>50% are not shown, and are replaced with the phrase “Data N/A due to high relative standard error.”

Social Determinants of Health (SDOH)

Social determinants of health are conditions in the places where people are born, live, learn, work, and play that affect health outcomes and overall quality of life. SDOH often drive health inequities, leading to health disparities in and among already vulnerable populations and communities. Healthy People 2030 categorizes SDOH into five domains:

• Economic stability
• Education access and quality
• Health care access and quality
• Neighborhood and built environment
• Social and community context

Sex

On this site, sex designations (male and female) are based on a person’s assigned sex at birth.

Stratified data

Data sorted into groups according to specified criteria such as age, race, or gender.

Surveillance

Systematic collection, analysis, interpretation, dissemination, and consolidation of data pertaining to the occurrence of a specific disease.

Transgender

This is an umbrella term that refers to persons whose sex assigned at birth does not match current gender identity or expression. Transgender woman refers to individuals who were assigned male sex at birth but have ever identified as female gender. Transgender man refers to individuals who were assigned female sex at birth but have ever identified as male gender.

Transmission Category

This is the term for the classification of cases that summarizes a person’s possible HIV risk factors; the summary classification results from selecting, from the presumed hierarchical order of probability, the one risk factor most likely to have resulted in HIV transmission. The exception is men who had sexual contact with other men and injected drugs; this group makes up a separate transmission category.

Transmission category data have been statistically adjusted to account for missing transmission category; therefore, values may not sum to column total.

Transmission category is classified based on a hierarchy of the risk factors most likely responsible for HIV transmission; classification is determined based on the person’s sex assigned at birth.

Persons whose transmission category is classified as male-to-male sexual contact include men who report sexual contact with other men (i.e., homosexual contact) and men who report sexual contact with both men and women (i.e., bisexual contact).

Persons whose transmission category is classified as injection drug use (IDU) are persons who injected non-prescribed drugs or who injected prescribed drugs for nonmedical purposes. Also includes injection of drugs prescribed to persons if there is evidence that injection equipment was shared.

Heterosexual contact includes persons who have ever had heterosexual contact with a person known to have, or with a risk factor for, HIV infection.

Other category includes other risk factors including, hemophilia, blood transfusion, perinatal exposure, and risk factor not reported or not identified.

Viral Suppression

If taken as prescribed, HIV medicine reduces the amount of HIV in the body (viral load) to a very low level, which keeps the immune system working and prevents illness. This is called viral suppression—defined as having less than 200 copies of HIV per milliliter of blood.