Office of AIDS
HIV Incidence Surveillance
FAQs and General Information
What is HIV Incidence Surveillance (HIS)?
HIV Incidence Surveillance (HIS) is an extension of routine HIV/AIDS case reporting, which provides demographic and clinical information on individuals who have received a confirmed diagnosis of HIV infection or AIDS from a healthcare provider. The goal of HIS is to provide national and area specific population-based estimates of the number of new HIV infections per year. HIS is a national effort developed and funded by the Centers for Disease Control and Prevention (CDC).
Why is HIS necessary?
It is not uncommon for people to be diagnosed with HIV long after they are infected. Therefore, changes in HIV/AIDS case counts alone have limited ability to describe the HIV epidemic.
Scientifically valid measures of HIV incidence provide information needed to increase our understanding of the HIV epidemic’s spread and provides a more accurate context in which to allocate resources for effective planning, implementation and evaluation of prevention programs and services.
How does HIS determine recent infections?
HIS is a fully integrated component of core HIV/AIDS surveillance, which provides demographic and clinical data on new HIV disease diagnoses reported by healthcare providers and laboratories. HIS combines information from HIV/AIDS case reports with patient testing and treatment history and results from a special laboratory test that distinguishes between recent and long-standing HIV infection to estimate new HIV infections from new HIV diagnoses using a stratified extrapolation approach. The special laboratory test that is used in incidence estimation is known as the Serologic Testing Algorithm for Recent HIV Seroconversion (STARHS).
What information is needed for HIS?
1) Patient's HIV testing and treatment history (TTH)
Frequency of HIV testing differs from person to person. Some people infected with HIV have tested for HIV multiple times before their first positive test result. Others find out that they are HIV positive the first time they test. The chances that someone is found to be recently infected by the STARHS test are greater if that person is a frequent HIV tester. Therefore, collecting HIV testing history makes it possible to account for variations in HIV testing frequency, providing a more accurate incidence estimate.
Patient treatment history is important because the STARHS test uses HIV-1 antibody levels to distinguish between recent and chronic infections. For this reason, STARHS tests are not performed on samples obtained from patients who have advanced HIV disease (AIDS). STARHS tests are also not performed on samples obtained from patients who have started antiretroviral therapy or who have received antiretroviral medications within six months of their first positive test (e.g., for treatment of Hepatitis or post-exposure prophylaxis).
The HIV testing and treatment history information needed for HIS includes the following:
(a) The dates of the patient’s first positive and last negative HIV test results.
(b) The number of times the patient tested for HIV during the 2 years prior to the first positive HIV test result.
(c) Whether or not the patient received any antiretroviral medications in the six months before the first positive test result.
HIV Testing and Antiretroviral Use History Form (CDPH 8681) (PDF)
2) Remnant diagnostic sera from HIV positive patients
The STARHS test is used on leftover specimens (e.g., blood or plasma) from newly diagnosed HIV cases. STARHS, which takes advantage of the average predicted rise in HIV-1 antibodies after infection to distinguish between recent and long-term HIV infection, was developed by the CDC specifically for population-based HIV incidence surveillance.
HIS Home Page