HIV Incidence Surveillance

HIV Incidence Surveillance is a supplemental HIV surveillance activity funded by the Centers for Disease Control and Prevention (CDC) and conducted in 25 areas across the United States including Virginia. The purpose of HIV incidence surveillance is to provide national and local estimates of the number of new HIV infections over a certain period of time. The Serologic Testing Algorithm for Recent HIV Seroconversion (STARHS) method in combination with HIV testing and antiretroviral use history data is used to estimate HIV incidence. The STARHS method uses a laboratory test to classify newly diagnosed HIV cases as either recent (occurring approximately within the last five months) or long standing HIV cases.

In general, incidence is expressed as the estimated number of persons newly infected with HIV during a specified time period (e.g., a year), or as a rate calculated by dividing the estimated number of persons newly infected with HIV during a specified time period by the number of persons at risk for HIV infection.

  • Example: An estimated 19,580 non-Hispanic whites were newly infected with HIV in the United States in 2006.
  • Example: The estimated rate of new HIV infections among non-Hispanic blacks was 83.8 per 100,000 population in the United States in 2006.

It is important to understand the difference between HIV incidence and a new diagnosis of HIV infection. HIV incidence refers to persons newly infected with HIV in a specified time period, whereas a person newly diagnosed with HIV may have been infected for years before being diagnosed.

Program Significance
While HIV case surveillance reporting allows for the measurement of the number of people newly diagnosed with HIV, it does not provide information about people who are newly infected. The testing technology used in HIV Incidence Surveillance allows for the estimation of HIV incidence at a population level both nationally and locally. The ability to do this is important for prevention evaluation and planning, public health policy development, resource allocation and to identify disease trends.

What is needed to Estimate HIV Incidence?

HIV incidence surveillance consists of two key components:

HIV Recency Testing
Recency testing distinguishes between recent (occurring approximately within the past five months) and long-standing HIV infection at the population level. The STARHS method uses a laboratory test (the BED HIV- Capture Enzyme) to make this distinction. The test is conducted on an HIV-1 antibody positive blood sample within 90 days of HIV diagnosis.

Testing and Treatment History (TTH)
State and local health department staff, and community based organizations that perform HIV testing complete a TTH questionnaire for each person who is newly diagnosed in Virginia. This questionnaire is used to obtain patient information regarding testing behaviors including testing frequency and antiretroviral medication use history.

These two components are integral to HIV incidence surveillance, as they provide the data that CDC and the state health department use to estimate the number of new HIV infections in a given year.

Additional Resources

Information regarding the CDC national HIV Incidence Surveillance program may be viewed at: and


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