HIV transmission at each step of the care continuum in the United States
23-Feb-2015 - Individuals infected but undiagnosed with the human immunodeficiency virus (HIV) and those individuals
diagnosed with HIV but not yet in medical care accounted for more than 90 percent of the estimated 45,000 HIV transmissions in 2009,
according to an article published online by JAMA Internal Medicine .
Preventing new HIV infections is essential to reducing future illness and death due to HIV infection in the United States. Interventions
at each step of the care continuum (diagnosis, retention in medical care, prescription of antiretroviral therapy [ART] and viral
suppression) have the potential to reduce HIV transmission. Estimates of the number of HIV transmissions arising at each step
of the HIV care continuum are essential for policy makers and programs to maximize the allocation of HIV prevention
resources, according to the study background.
Jacek Skarbinski, M.D., of the Centers for Disease Control and Prevention, Atlanta, and coauthors estimated the rate and number of HIV
transmissions attributed to people at each of five care continuum steps: infected but undiagnosed, diagnosed but not in medical care,
retained in medical care but not prescribed ART, prescribed ART but not virally suppressed, and achieved viral suppression. The
authors used national databases to estimate rates and transmission numbers in the HIV-infected population in the United States in 2009.
According to study results, there were more than 1.1 million people living with HIV in 2009. Of those, 207,600 (18.1 percent) were
undiagnosed; 519,414 (45.2 percent) knew of their infection but were not in medical care; 47,453 (4.1 percent) were in medical care
but not prescribed ART; 82,809 (7.2 percent) were prescribed ART but not virally suppressed; and 290,924 (25.3 percent) had
achieved viral suppression.
Those individuals who were infected with HIV but undiagnosed and those individuals who were diagnosed with HIV but not in medical care
accounted for 91.5 percent (30.2 percent and 61.3 percent, respectively) of the estimated 45,000 transmission in 2009.
Compared with individuals who were HIV infected but undiagnosed (6.6 transmissions per 100 person-years), individuals diagnosed with HIV
and not in medical care were 19 percent less likely to transmit HIV (5.3 transmissions per 100 person-years) and individuals who were
virally suppressed were 94 percent less likely to transmit HIV (0.4 transmissions per 100 person-years). Men accounted for the most
transmissions (86.5 percent).
"In the United States, persons living with HIV who are retained in medical care and have achieved viral suppression are 94 percent less
likely to transmit HIV than HIV-infected undiagnosed persons. Unfortunately, too few persons living with HIV have achieved viral
suppression. These estimates of the relative number of transmissions from persons along the HIV care continuum highlight the
community-wide prevention benefits of expanding HIV diagnosis and treatment in the United States. Improvements are needed
at each step of the continuum to reduce HIV transmission. Through stronger coordination of efforts among individuals,
HIV care providers, health departments and government agencies, the United States can realize meaningful gains in
the number of persons living with HIV who are aware of their status, linked to and retained in care, receiving
ART, and adherent to treatment," the study concludes.
(JAMA Intern Med. Published online February 23, 2015. doi:10.1001/jamainternmed.2014.8180. Available pre-embargo to the media
Editor's Note: The Centers for Disease Control and Prevention provides funds to all states and the District of Columbia to conduct
the HIV surveillance used in this study and to selected areas to conduct the Medical Monitoring Project and the National HIV
Behavioral Surveillance System. Please see the article for additional information, including other authors, author
contributions and affiliations, financial disclosures, funding and support, etc.
Commentary: The HIV Treatment Cascade - A New Tool in HIV Prevention
In a related commentary, Thomas P. Giordano, M.D., M.P.H., of the DeBakey Veterans Affairs Medical Center, Houston, writes: "Not
surprisingly then, the study demonstrates that the steps of the cascade that propel HIV transmission in the United States are
delayed diagnosis and inadequate retention in care. However, what is surprising is the magnitude of the effect of those
steps: the authors estimate that more than 90 percent of transmissions in the United States can be attributed to
undiagnosed HIV and poor retention in care."
"Just as there is no single approach to improving adherence to antiretroviral therapy, there likely will be no single approach to
improving linkage to and retention in HIV care. Human behavior and the health care system are too complex," the author continues
"Advancing individuals forward from the beginning to the end of the cascade will place a more challenging population on antiretroviral
therapy regimens, and fostering their success might require even more supportive resources. Nonetheless, as demonstrated by Skarbinski
et al, the benefits of optimizing treatment to the individual will be magnified on a population basis in preventing new
infections," Giordano concludes.
(JAMA Intern Med. Published online February 23, 2015. doi:10.1001/jamainternmed.2014.8199. Available pre-embargo to the media
Editor's Note: This work was made possible with help from the Baylor-UTHouston Center for AIDS Research and the resources and
facilities of the Department of Veterans Affairs and the Harris Health System. Please see the article for additional
information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.
Media Advisory: To contact author Jacek Skarbinski, M.D., call Nikki Mayes at 404-639-6258 or email email@example.com. To contact commentary author Thomas P. Giordano, M.D., M.P.H., call Maureen Dyman at 713-794-7349 ext. 25569 or email firstname.lastname@example.org or call Dipali Pathak at 713-798-4710 or email email@example.com.
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