Test-and-treat strategies for HIV prevention involve early
diagnosis and linkage to care, retention in care, and sustained
antiretroviral therapy (ART) in order to increase the proportion
of patients with undetectable viral load. For test-and-treat to
be successful, a person who is HIV-infected must experience a
sequence of events beginning with diagnosis, proceeding through
engagement in medical care, and culminating in an undetectable
viral load. Gardner, et al, called this the "spectrum of
engagement in care." (1) Gardner used findings from published
literature to specify the proportion of living cases who were
undiagnosed and those who were subsequently linked to care,
retained in care, on ART and had undetectable viral load. We
used data reported to the Oregon STD/HIV/TB Program to specify
these proportions based on observations in Oregon.* (Figure 1)
Stage of Engagement in HIV Care among Oregon residents, 2011
Figure 1: Estimates of the number of people infected with HIV at
each stage of Gardner's spect