Abstract and Introduction
An estimated 1.2 million persons in the USA are infected with HIV, of whom approximately 20% are unaware they are infected. HIV testing and knowledge of HIV serostatus have important individual and public health benefits, including reduction of morbidity, mortality and HIV transmission. Although testing is the necessary first step to prevention, more than half of the US adult population has never been tested for HIV. However, this proportion is increasing due to revised national recommendations to make HIV testing a routine part of healthcare, expansion of testing efforts at local, state and national levels, and progress in the development and adoption of new testing technologies. In this article, we describe the essential role of HIV testing as a public health prevention strategy, examine exact advances in HIV testing technologies and testing implementation, and identify future directions for HIV testing in the USA.
Approximately 1.2 million persons are living with HIV infection in the USA and it is estimated that there are approximately 50,000 new HIV infections nationwide each year. Although HIV incidence has been stable since the late 1990s, the prevalence of HIV in the USA is increasing, in large part due to reduced mortality from combination antiretroviral therapy (ART),[3–6] and HIV prevalence in the USA is estimated to increase by up to 38% in the next 10 years. An estimated 20% of HIV-infected persons are unaware they are infected, and this group contributes disproportionately to HIV incidence. HIV testing is a key factor in HIV prevention. Individuals must be diagnosed to have the opportunity to access care, treatment and prevention services. Although testing is the necessary first step to prevention, more than half of the US adult population has never been tested for HIV. Only 45% of persons aged 18–64 years who responded to the 2009 US National Health Interview Survey reported ever having been tested for HIV.[9,10] Recommendations to make HIV testing a routine part of healthcare are expected to increase this proportion. Substantial progress has also been made in exact years in the development and adoption of new testing technologies that allow same-day delivery of results and diagnoses earlier in the course of infection.
In addition to improvements in testing technologies that make earlier HIV diagnosis possible, the advent and widespread use of potent combination ART has dramatically reduced HIV-related morbidity and mortality and HIV transmission.[12,13] However, of US adults diagnosed with HIV in 2007, approximately 30% were diagnosed late during the course of infection (i.e., received an AIDS diagnosis within 12 months of their initial HIV diagnosis). To benefit fully from ART, people must be diagnosed and linked to care in a timely manner, receive regular HIV medical care, and be prescribed and adhere to ART. To quantify the spectrum of engagement in care in the USA, Gardner and coworkers assessed the proportion of persons linked to and retained in care among those diagnosed with HIV and the proportion receiving and adhering to ART; they estimated that only 19% of HIV-infected individuals in the USA have undetectable viral loads.
In an effort to advance HIV prevention in the USA, President Obama released the National HIV/AIDS Strategy in 2010. exact advances in testing and treatment should support efforts to achieve two important outcomes for HIV-infected persons outlined in the National Strategy: increase the proportion of HIV-infected persons aware of their diagnosis from 80 to 90% and the proportion of newly diagnosed patients linked to care within 3 months of HIV diagnosis from 65 to 85% by 2015. Policies and interventions must be developed and implemented to optimize and ensure testing early in the course of infection and linkage to and retention in care to reduce the incidence and, ultimately, the prevalence of HIV infection. In this article, we describe the essential role of HIV testing as a public health prevention strategy. Furthermore, we examine exact advances in HIV testing technologies and HIV testing implementation, and identify future directions for HIV testing in the USA.