The modified social ecological model (MSEM)
The MSEM is composed of five layers of risk for HIV infection:
individual, network, community, policy, and
stage of the HIV epidemic. The MSEM modifies the social
ecological model by modifying the levels of risk as
well as adding the stage or level of the HIV epidemic to
the social ecological model, and is based on the premise
that while individual level risks are necessary for the
spread of disease, they are insufficient to explain population
level epidemic dynamics. The higher order social
and structural levels of risk (network, community, policy,
stage of epidemic) represent risk factors outside of
the control of any individual person [13]. And though
policy makers tend to target interventions at individual
level risks, they are only one component affecting the
transmission of HIV among marginalized populations
[2,4,9]. We present an MSEM figure that highlights
these levels of risk (Figure 1) that can be adapted to
contextualize HIV transmission risk among vulnerable
populations. Factors can span levels and therefore the
boundaries between levels may be understood as porous
rather than distinct.