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Using Interrupted Time Series Analysis to Measure the Impact of Legalized Syringe Exchange on HIV Diagnoses in Baltimore and Philadelphia


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Background: Syringe exchange programs (SEP) reduce HIV incidence associated with injection drug use (IDU), but legislation often prohibits implementation. We examined the policy change impact allowing for SEP implementation on HIV diagnoses among people who inject drugs in 2 US cities. Setting: Philadelphia, PA, and Baltimore, MD. Methods: Using surveillance data from Philadelphia (1984-2015) and Baltimore (1985-2013) for IDU-associated HIV diagnoses, we used autoregressive integrated moving averages modeling to conduct 2 tests to measure policy change impact. We forecast the number of expected HIV diagnoses per city had policy not changed in the 10 years after implementation and compared it with the number of observed diagnoses postpolicy change, obtaining an estimate for averted HIV diagnoses. We then used interrupted time series analysis to assess the immediate step and trajectory impact of policy change implementation on IDU-attributable HIV diagnoses. Results: The Philadelphia (1993-2002) model predicted 15,248 new IDU-associated HIV diagnoses versus 4656 observed diagnoses, yielding 10,592 averted HIV diagnoses over 10 years. The Baltimore model (1995-2004) predicted 7263 IDU-associated HIV diagnoses versus 5372 observed diagnoses, yielding 1891 averted HIV diagnoses over 10 years. Considering program expenses and conservative estimates of public sector savings, the 1-year return on investment in SEPs remains high: $243.4 M (Philadelphia) and $62.4 M (Baltimore). Conclusions: Policy change is an effective structural intervention with substantial public health and societal benefits, including reduced HIV diagnoses among people who inject drugs and significant cost savings to publicly funded HIV care.
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Using Interrupted Time Series Analysis to Measure the
Impact of Legalized Syringe Exchange on HIV Diagnoses in
Baltimore and Philadelphia
Monica S. Ruiz, PhD, MPH,
Allison ORourke, MPH,
Sean T. Allen, DrPH, MPH,
David R. Holtgrave, PhD,
David Metzger, PhD,
Jose Benitez, MSW,
Kathleen A. Brady, MD,
C. Patrick Chaulk, MD, MPH,
and Leana S. Wen, MD
Background: Syringe exchange programs (SEP) reduce HIV
incidence associated with injection drug use (IDU), but legislation
often prohibits implementation. We examined the policy change
impact allowing for SEP implementation on HIV diagnoses among
people who inject drugs in 2 US cities.
Setting: Philadelphia, PA, and Baltimore, MD.
Methods: Using surveillance data from Philadelphia (19842015)
and Baltimore (19852013) for IDU-associated HIV diagnoses, we
used autoregressive integrated moving averages modeling to conduct
2 tests to measure policy change impact. We forecast the number of
expected HIV diagnoses per city had policy not changed in the 10
years after implementation and compared it with the number of
observed diagnoses postpolicy change, obtaining an estimate for
averted HIV diagnoses. We then used interrupted time series analysis
to assess the immediate step and trajectory impact of policy change
implementation on IDU-attributable HIV diagnoses.
Results: The Philadelphia (19932002) model predicted 15,248
new IDU-associated HIV diagnoses versus 4656 observed diagno-
ses, yielding 10,592 averted HIV diagnoses over 10 years. The
Baltimore model (19952004) predicted 7263 IDU-associated HIV
diagnoses versus 5372 observed diagnoses, yielding 1891 averted
HIV diagnoses over 10 years. Considering program expenses and
conservative estimates of public sector savings, the 1-year return on
investment in SEPs remains high: $243.4 M (Philadelphia) and
$62.4 M (Baltimore).
Conclusions: Policy change is an effective structural intervention
with substantial public health and societal benets, including
reduced HIV diagnoses among people who inject drugs and
signicant cost savings to publicly funded HIV care.
Key Words: injection drug use, HIV, syringe exchange, policy
change, cost-effectiveness
(J Acquir Immune Dec Syndr 2019;82:S148S154)
Syringe exchange programs (SEP), also known as needle
exchange programs or syringe access programs, are an essential
component to preventing HIV/AIDS among people who inject
drugs (PWID). Studies have shown that SEP utilization is
associated with reductions in bloodborne infections among
PWID; research from Tacoma, WA,
New Haven, CT,
New York City, NY,
has demonstrated that SEP implementa-
tion was associated with signicant reductions in hepatitis B and
C incidence (80% reduction)
and HIV incidence (estimated
Despite evidence demonstrating the public health
utility of SEPs,
federal and state policies (eg, drug parapher-
nalia laws) may limit their implementation. Other policies more
explicitly affect SEP operations. In 1988, Congress passed
legislation prohibiting the use of federal monies to support SEPs.
Aside from a brief period (20092012) during which the
restriction was removed, the legislation remained until Decem-
suburban and rural populations injecting prescription opioids,
the language was modied to allow federal monies to support
SEP operations except for purchasing injection equipment.
From the
Department of Prevention and Community Health, Milken Institute
School of Public Health, George Washington University, Washington, DC;
Department of Sociology, Center for Health, Risk, and Society, American
University, Washington, DC;
Department of Health, Behavior, and
Society, Johns Hopkins Bloomberg School of Public Health, Baltimore,
Department of Psychiatry, Perelman School of Medicine, University
of Pennsylvania, Philadelphia, PA;
Treatment Research Institute, Phila-
delphia, PA;
Prevention Point Philadelphia, Philadelphia, PA;
Activities Coordinating Ofce, Philadelphia Department of Public Health,
Philadelphia, PA;
Bureau of HIV/STD Services, Baltimore City Health
Department, Baltimore, MD; and
Ofce of the Commissioner, Baltimore
City Health Department, Baltimore, MD.
This publication resulted in part from research supported by the Penn Center
for AIDS Research (CFAR) (P30 AI 045008 - Ronald Collman, PI), the
Penn Mental Health AIDS Research Center (PMHARC) (P30 MH
097488 - Dwight Evans, PI) and the CFAR Social & Behavioral Science
Research Network National Scientic Meeting (SBSRN) (R13 HD
074468 - Michael Blank, PI).
The authors have no conicts of interest to disclose.
Correspondence to: Monica S. Ruiz, PhD, MPH, Milken Institute School of
Public Health, George Washington University, 950 New Hampshire
Avenue, Suite 300, Washington, DC 20052 (e-mail:
Copyright © 2019 The Author(s). Published by Wolters Kluwer Health, Inc.
This is an open-access article distributed under the terms of the Creative
Commons Attribution-Non Commercial-No Derivatives License 4.0
(CCBY-NC-ND), where it is permissible to download and share the
work provided it is properly cited. The work cannot be changed in any
way or used commercially without permission from the journal.
S148 | J Acquir Immune Defic Syndr Volume 82, Supplement 2, December 1, 2019
SEP Case Histories: Philadelphia
and Baltimore
For Philadelphia and Baltimore in the 1990s, changing
paraphernalia legislation was critical to creating SEPs.
SEPs in Philadelphia originated when activists orga-
nized a community response to rising HIV infection rates
among PWID.
Pennsylvanias paraphernalia laws were
conicting: syringe possession and distribution were illegal
in Philadelphia,
but the Disease Prevention and Control Act
of 1955 authorized syringe distribution as a disease pre-
vention activity within individual cities. Seeing the AIDS
epidemic as a public health emergency, activists felt that the
Disease Prevention and Control Act authorized SEPs as
a public health measure. In late 1991, Prevention Point
Philadelphia (PPP) was created, operating illegally while
working with and gaining support from the health commis-
sioner, ofcials at the Department of Healths AIDS Ofce
(now the AIDS Activities Coordinating Ofce), and the
Despite state disapproval, the mayor signed Exec-
utive Order 492 on July 27, 1992, declaring HIV/AIDS
a public health emergency in Philadelphia and authorizing
SEPs as a measure to address it.
On August 1, 1992, PPP
held its rst day of legal syringe exchange. Although data
pertaining to syringe distribution from the initial years of PPP
are not available, SEP operationsdata from 1998 indicate
that over 400,000 syringes were distributed during this year,
with that amount almost doubling to 810,000 in 1999. In each
of these years, over 2000 new clients were registered. PPP
remains the sole ofcially recognized SEP in Philadelphia,
providing syringe access and harm reduction services
(including medical care, wound care, HIV/HCV testing,
overdose prevention and reversal training, linkage to drug
treatment, and medication-assisted treatment) through munic-
ipal and private support.
Baltimores legislative environment was also the big-
gest obstacle to SEP implementation. Marylands Uniform
Controlled Dangerous Substances Act of 1970 made drug
paraphernalia possession illegal. For SEPs to open in
Baltimore, state laws needed to change. The impetus for
change came in 1992 from the citys own leadership: the
mayor and the health commissioner. They lobbied the state
legislature for exemptions to existing paraphernalia laws for
Baltimore City so the Health Department could legally
distribute sterile injection equipment. Early attempts at policy
change were met with resistance from the Governor and other
state legislators, but eventually, Senate Bill 402 was signed in
to law on April 2, 1994,
and went into effect on June 1,
1994. Since then, the Baltimore City Health Department has
run the SEP.
In addition to syringe access services, the SEP
provides harm reduction education, linkage to addiction
treatment services (including maintaining same day treatment
openings), testing and counseling for HIV and syphilis, and
opioid overdose response training.
Why Policy Change Matters
These stories show 2 different mechanisms of policy
change for SEP establishment; they also underscore the
importance of policy change as a structural intervention for
HIV prevention among PWID in that it changes individuals
risk environment without changing their behaviors or social
Our study in the District of Columbia (DC)
found that changing legislation to allow the use of municipal
revenue for SEPs in 2008 was associated with an estimated
120 averted HIV diagnoses in PWID in the rst 2 years after
policy change and an estimated savings of $44.3 million in
health care costs associated with HIV treatment.
Given the historical contexts of Philadelphia and
Baltimore, would one expect the same magnitude of epidemic
impact that was observed in DC? We examined this question
using similar methodologies used in the examination of
policy change impact in DC.
Although previous research
has examined the association between presence of SEPs and
HIV incidence, these studies were more ecological in nature.
We build on these previous analyses by not only examining
how SEP implementation affected the HIV epidemic in each
city but also by attempting to isolate the epidemic impact of
policy change specically on the numbers of new
HIV diagnoses.
Using autoregressive integrated moving averages (ARI-
MA) modeling, forecasts were created to estimate the
expected annual number of new HIV diagnoses that would
have occurred in the 10 years had policies not changed.
Forecasted numbers for each city were then compared with
observed numbers of diagnoses to calculate the averted new
HIV diagnoses that could be attributed to legal SEP
implementation. We then used interrupted time series analysis
(ITSA) to assess the impact that policy change (the inter-
ruption) had on injection drug use (IDU)associated HIV
diagnoses, both immediately and as a trend change. ITSA
examines temporally ordered data to determine whether an
experimental manipulation or intervention produced a reliable
change in data
while also allowing models to account for
baseline levels and trends present in the data. Henceforth, we
refer to observations before the interruption as the pre-
implementation periodand those after the interruption as the
postimplementation period.
The outcome measure for both cities was IDU-
associated HIV diagnoses. In Philadelphia, data were ex-
tracted from Philadelphias Enhanced HIV/AIDS Reporting
System (eHARS), a population-based registry containing
information on all HIV/AIDS diagnoses reported to the
Philadelphia Department of Public Health AIDS Activities
Coordinating Ofce Surveillance Unit since 1984. eHARS
contains information abstracted from medical records, includ-
ing HIV transmission risk (eg, IDU and MSM/IDU) and
laboratory reporting of all CD4 cell counts and HIV-1 RNA
levels. Thus, eHARS contains data from all people living with
HIV (PLWH) diagnosed in Philadelphia.
Annual numbers of HIV diagnoses in Baltimore were
extracted from the Baltimore City Annual HIV Epidemiolog-
ical Prole,
which contains data reported to the state
through December 31, 2014. Annual percentages of diagno-
ses attributed to each exposure category are reported for the
Impact of Legalized Syringe ExchangeJ Acquir Immune Defic Syndr Volume 82, Supplement 2, December 1, 2019
Copyright © 2019 The Author(s). Published by Wolters Kluwer Health, Inc. |S149
years 19852013. To determine the annual number of IDU-
associated HIV cases, the percentages of new HIV diagnoses
with a known exposure risk were multiplied by each IDU-
associated exposure category (IDU and MSM/IDU). These 2
numbers were combined for each year to represent the total
number of new IDU-associated HIV diagnoses.
ARIMA models were t to the preimplementation data
for each city using Box and Jenkins
methods. Outlier
detection was completed to identify signicant (a,0.01)
shift and additive observations. Shift outliers were addressed
in the model by entering dichotomous variables assigning 0 to
observations prior to and 1 to all other observations including
and following the identied shift outlier. For additive outliers,
dichotomous variables were added to the model, assigning 1
to the additive outlier and 0 to all other observations.
ITSA models evaluated 2 types of impactstep change
and slope changeon new HIV diagnoses. Step change tests
for an immediate signicant change between HIV diagnoses
in the last preperiod and rst postperiod observations. It was
measured with a dichotomous variable that assigned 0 to all
prepolicy and 1 to all postimplementation observations. Slope
change tests for signicant changes in trend and direction of
the number of HIV diagnoses across the preperiod versus the
postperiod. It was measured using a continuous variable that
assigned 0 to all preimplementation observations and 1 to the
rst postinterruption observation, with subsequent observa-
tion values increasing by 1 (1, 2, ., n).
For the ITSA, the year ending after the date of policy
change was used as the interruption. In the 6 months after each
policy change, surveillance efforts and normal testing mecha-
nisms would have been more likely to detect those who are
already HIV-positive. Therefore, the real policy impact would
have occurred after persons already living with HIV and
previously undiagnosed were detected and after legal SEPs were
operating and effectively reaching PWID. In Philadelphia, legal
SEP began on August 1, 1992, so the data were divided into 2
periods: preimplementation (1984 through 1992) and postim-
plementation (1993 through 2015). Baltimores legal SEP began
on June 1, 1994, so data were similarly divided into preimple-
mentation (1985 through 1994) and postimplementation (1995
through 2013) periods. In using annual data, our analyses attempt
to conservatively account for the possible lag time between when
the policy changed and when it started to have epidemic impact.
In addition, we replicated these methods in Baltimore
using HIV diagnoses data among MSM without IDU
exposure to examine the true impact of SEP utilization on
new HIV diagnoses (ie, as a control). Notably, these analyses
were only possible in Baltimore given HIV case-reporting
data availability. Given that MSM in Baltimore would be
similar to the PWID population in terms of exposure to public
health efforts (eg, changes in HIV testing and access to HIV
treatment) that would have been available during the same
time period, these analyses allow us to control for other
variables that may have affected new cases of HIV and better
understand the true impact of SEP implementation on IDU-
associated HIV diagnoses. All analyses were completed using
SAS v9.4. This research was determined by the George
Washington Universitys Institutional Review Board as
exempt from oversight (IRB #051106).
Descriptive measures for the epidemiologic data are
presented in Table 1. For Philadelphia, we observed a non-
signicant preimplementation to post implementation
decrease in the mean number of new IDU-associated HIV
diagnoses (419.9 and 291.6, respectively) as well as a signif-
icant preimplementation to post implementation decrease in
the MSM/IDU exposure category (77.7 and 35.6, P,0.05).
For Baltimore, we observed a signicant preimplementation
to postimplementation decreases in both in the mean number
of IDU-associated HIV diagnoses (607.9 and 357.0, P,
0.05) and the mean numbers of new diagnoses attributed to
each IDU exposure category (IDU only: 542.8 and 332.2, P
,0.05, MSM/IDU: 65.0 and 24.8, P,0.05).
For Philadelphia, an ARIMA (0, 1, 0) model with 4
outliersshift outliers at 1989 and 1990 and additive outliers
at 2002 and 2005was determined to be the best t for the
data. The 1989 and 1990 shift outliers were included in all
analyses; the 2002 and 2005 additive outliers were only
included in the ITSA. The model forecasts 15,248 new IDU-
associated HIV diagnoses in Philadelphia between 1993 and
2002, whereas 4656 IDU-associated HIV diagnoses were
reported (Fig. 1). This is a difference of 10,592 averted
diagnoses of HIV over 10 years (approximately 1059 averted
diagnoses annually). Using annual HIV case data from 1984
to 2015, ITSA was completed to determine whether SEP
implementation resulted in an immediate step or trend change
between the preimplementation and postimplementation peri-
ods. A signicant negative step change (B = 2162.5,
P,0.001) was identied, as was a signicant decreasing
slope change (B = 2115.5, P,0.001) (Table 2).
For Baltimore, an ARIMA (1, 1, 0) model with one
order of nonseasonal differencing and a single autoregressive
TABLE 1. Annual New Diagnoses of IDU-Associated HIV
Infection: Baltimore and Philadelphia
Prepolicy Period,
Mean (SD)
Postpolicy Period,
Mean (SD)
Mean (SD)
IDU exposure 342.2 (300.4) 256.0 (179.3) 280.25 (218.3)
MSM and
77.7 (39.6) 35.61 (17.7)* 47.4 (31.6)
Total 419.9 (336.9) 291.6 (196.3) 327.7 (245.1)
IDU exposure 542.8 (267.5) 332.2 (211.7)* 404.8 (249.4)
MSM and
65.0 (21.6) 24.78 (16.0)* 38.7 (26.3)
Total 607.9 (281.0) 357.0 (226.7)* 443.48 (270.4)
*Studentst-test, P,0.05 comparing pre interruption and postinterruption values.
Ruiz et al J Acquir Immune Defic Syndr Volume 82, Supplement 2, December 1, 2019
S150 | Copyright © 2019 The Author(s). Published by Wolters Kluwer Health, Inc.
term was determined as the best t for the data. The 10-year
forecast predicted 7263 new IDU-associated HIV diagnoses
in Baltimore between 1995 and 2004, whereas 5372 diagno-
ses were reported (Fig. 2). This is a difference of 1891 averted
HIV diagnoses over 10 years, with 207 averted cases in the
rst 5 years (11% of total predicted averted cases) and 1684
in years 6 through 10 (89% of total predicted averted cases).
Using surveillance data for 1985 to 2013, ITSA was
completed to assess signicant immediate and slope changes
between the preimplementation and postimplementation peri-
ods. No signicant immediate step (B = 55.34 P= 0.4368) or
slope (B = 283.41, P= 0.0852) change was identied
(Table 2).
With respect to the control model in Baltimore that used
MSM-attributed HIV diagnoses, the ITSA found no signi-
cant immediate step change or slope change for new cases of
HIV after SEP implementation (Fig. 3). In addition, the
forecasting showed only a small difference between the
observed (1,345) and expected (1,776) cases of MSM-
attributed HIV in the 10 years after the SEP policy change.
These analyses demonstrate that SEP implementation in
Philadelphia and Baltimore was associated with signicant
overall reductions in IDU-associated HIV diagnoses. Phila-
delphiasndings are particularly striking: the signicant step
and slope changes observed indicate that policy change and
SEP implementation occurred in the same year as the number
of HIV diagnoses was peaking. Although it cannot be stated
with 100% certainty that the epidemic trajectory would have
leveled after reaching that apex, the ARIMA forecast suggests
that diagnoses would have continued to rise had SEP
implementation not taken place. The signicant level-shift
outliers identied in 1989 and 1990 during the prepolicy
change period indicate that Philadelphia had a signicant
increase in new HIV diagnoses during these 2 consecutive
years that persisted for many years following. The additive
outliers identied in 2002 and 2005 mark 2 years that had
signicantly higher numbers of reported new HIV cases;
however, these changes did not persist or impact observations
seen in the following years. Of interest and likely the
explanation for these 2 outliers, Philadelphia moved to
code-based reporting in 2002 and name-based reporting in
2005. These data support the possibility that the policy
change in Philadelphia may have capped the peak of IDU-
associated diagnoses in the city, explaining the rapid decrease
in IDU-associated diagnoses after 1995.
The Baltimore data also showed a decrease in IDU-
associated HIV diagnoses after the policy change.
Although the surveillance data show that IDU-associated
HIV diagnoses had begun to stabilize and decrease slightly
before SEP implementation, the addition of SEPs contrib-
uted to a more rapid decline. The comparison of the more
rapid decline in IDU-associated cases and the slower
decline in the number of MSM-associated cases indicates
that although other factors occurring within Baltimore
likely played some role in the decrease in HIV seen among
PWID, the vast majority of this decrease can be attributed
to SEP implementation.
FIGURE 1. Forecasted versus actual
diagnoses of IDU-associated HIV infec-
tion in Philadelphia during the 10 years
after the change in syringe exchange
TABLE 2. Interrupted Time Series Analysis: Philadelphia and
Value P
Philadelphia ARIMA (0, 1, 0)
Constant 79.0 6.57 ,0.0001
Shift outlier1989 103.0 3.24 0.0035
Shift outlier1990 149.0 4.68 ,0.0001
Additive outlier2002 90.0 4.32 0.0002
Additive outlier2005 117.53 3.9 0.0007
Immediate effect of policy
2162.5 25.39 ,0.001
Change in trend postpolicy
2115.5 28.47 ,0.001
Baltimore ARIMA (1,1,0)
Constant 51.30 1.38 0.1790
AR term 0.41 1.99 0.0576
Immediate effect of policy
55.33 0.79 0.4368
Change in trend postpolicy
283.41 21.80 0.0852
Impact of Legalized Syringe ExchangeJ Acquir Immune Defic Syndr Volume 82, Supplement 2, December 1, 2019
Copyright © 2019 The Author(s). Published by Wolters Kluwer Health, Inc. |S151
Limitations must be acknowledged in this research, the
rst pertaining to the quantity and quality of available
surveillance data for each city. Although AIDS case surveil-
lance in both cities began in the mid-1980s, HIV case
reporting (either by name or code) was implemented much
later; in Baltimore, code reporting began in 1994 and name
reporting began in 2007, whereas in Philadelphia, code
reporting began in 2002 and name reporting began in 2005.
Since SEPs in both cities started in the early to mid-1990s,
there were fewer observations of annual HIV diagnoses
before the policy change event despite having sufcient
numbers of observations to meet the minimum requirements
for ARIMA modeling. More prepolicy change observations
would have facilitated a more nely tunedmodel that better
reects longitudinal trends in IDU-associated HIV diagnoses.
Also, our analyses modeled HIV diagnoses rather than
incidence due to data limitations. Whether diagnoses are
a good proxy for incidence depends on various factors,
including stage of the local HIV epidemic, the number of
PLWH unaware of their status, and the availability of local
testing programs. Furthermore, data obtained from city health
departments for these analyses may reect issues present in
disease surveillance systems, including inconsistencies in
HIV/AIDS case reporting and variability in PWIDsHIV
testing patterns. Effects observed in both cities may actually
underestimate impact given potential overlaps between diag-
noses of IDU-associated and heterosexual transmission, as
well as the availability and utilization of other interventions
for PWID such as addiction treatment and access to
antiretroviral medication.
Anal point of consideration pertains to the determi-
nation of HIV epidemic impact of policy change within the
PWID population when there are no precise size estimates of
this population. Although estimates of the overall PWID
population has remained stable from 1992 to 2002, there have
been estimates of growing PWID populations in Baltimore
(168336 per 10,000 population) and the PhiladelphiaNew
Jersey MSAs (from 151 to 173 per 10,000 population).
Given that the time period for these estimates is similar to that
of our analyses, we are condent that our estimates are
measuring true population impact.
Our ndings also demonstrate that averted HIV diag-
noses translated to cost savings for cities where most PLWH
are recipients of publicly funded healthcare. The forecasts
estimated an average of 1059 HIV diagnoses in Philadelphia
and 189 HIV diagnoses in Baltimore averted annually.
Multiplying the lifetime costs of HIV treatment per person
by the average number of diagnoses averted
annually in both cities yields an estimated annual saving of
$243.4 million for Philadelphia and $62.4 million for
Baltimore. Considering diagnoses averted over the 10-year
modeled period, the lifetime cost savings associated with
averted HIV diagnoses stemming from policy change to
support SEPs may be more than $2.4 billion and $624 million
FIGURE 2. Forecasted versus actual
diagnoses of IDU-associated HIV diag-
noses in Baltimore during the 10 years
after the change in syringe exchange
FIGURE 3. Forecasted versus actual
diagnoses of IDU-associated and MSM-
associated HIV diagnoses (control case
scenario) in Baltimore during the 10
years after the change in syringe
exchange policy.
Ruiz et al J Acquir Immune Defic Syndr Volume 82, Supplement 2, December 1, 2019
S152 | Copyright © 2019 The Author(s). Published by Wolters Kluwer Health, Inc.
dollars for Philadelphia and Baltimore, respectively. Because
SEPs are relatively inexpensive to operate,
overall cost
savings are substantial even when deducting program oper-
ational costs from the total amount. Considering annual
program expense ($390,000 in 2011 for Philadelphia
$800,000 estimated in FY 2017 for Baltimore
) (Kathleen
Goodwin, Baltimore City Health Department, personal
communication, January 3, 2017) and cost savings in each
city, and a conservative estimate that 75% of these savings
would be experienced in the public sector, the 1-year return
on investment in SEPs remains in the hundreds of millions
of dollars ($182.5 M for Philadelphia, $46.8 M for
Baltimore). Small investments in SEPs may yield large
savings in HIV treatment costs, so implementing SEPs may
liberate resources for other important interventions, such as
expanded access to medication-assisted treatment, overdose
prevention, and housing.
Another implication pertains to how variations in SEP
implementation may have inuenced intervention effective-
ness. Policies governing SEPs affect not only the overall
number of syringes distributed annually but also the ability of
PWID to obtain sufcient coverage for all injection events.
For example, PPPs clients may exchange syringes for
themselves and others; recent data show that the mean
number of syringes exchanged per exchange event increased
from 1.53 in 1999 to 1.82 in 2014.
In addition, PPPs
annual syringe distribution has consistently increased from
approximately 811,000 in 1999 to 1.2 million in 2014,
allowing for greater coverage of injection events and more
opportunities for disease prevention.
By contrast, Baltimores SEP had a one-for-one (1:1)
exchange policy from 1994 to 1999 but, in 2000, switched to
a more restrictive policy, where clients were allowed 1:1
exchange for program-distributed syringes but could receive 1
sterile syringe in exchange for 2 nonprogram syringes. From
2005 to 2014, the SEP returned to the less restrictive 1:1
policy, after which they shifted to a need-based distribution
model whereby PWID could access as many syringes as
needed. Baltimore Citys health commissioner estimated that
moving from the 1:1 to the needs-based distribution policy
could increase coverage of injection events from 42% to
More exible approaches to syringe access in
Baltimore could have resulted in greater injection coverage
and more dramatic declines in IDU-associated HIV diagnoses
earlier. Regulations limiting clean needle and syringe distri-
bution are important operational issues to consider if policy
changes supporting harm reduction for PWID are to have
optimal impact.
This research provides additional support for the
effectiveness of policy change as a structural intervention
for HIV prevention among PWID and the utility of syringe
access as an effective, evidence-based approach to promote
PWID health. The need for such approaches is particularly
relevant given the current state of the opioid epidemic in the
United States and the resurgence of IDU-associated HIV
outbreaks in suburban and rural areas. A critical lesson
learned from the Indiana HIV outbreak was that had the
SEP been implemented earlier in the course of that outbreak,
many infections could have been averted. Communities
throughout the United States which are vulnerable to IDU-
associated HIV outbreaks should consider the potential public
health benets, such as those experienced in Philadelphia and
Baltimore; they may gain from implementing SEPs as they
are one of our most powerful HIV prevention strategies for
PWID populations.
This work is part of a larger projectDC POINTE:
Policy Impact on the Epidemicwhose main objective is to
examine the epidemic impact of policy change as a structural
intervention for HIV prevention for PWID in the District of
Columbia. This research was supported by a grant from the
National Institute on Drug Abuse (NIDA) to M.S.R.
(R01DA031649). The authors of this paper have no conicts
of interest to declare.
We would also like to acknowledge the infrastructure,
core, and administrative support provided by the District of
Columbia Center for AIDS Research (CFAR; P30AI087714),
the Penn Center for AIDS Research (CFAR; P30 AI045008),
the Penn Mental Health AIDS Research Center (PMHARC;
P30MH097488), and the Johns Hopkins University Center
for AIDS Research (CFAR; P30AI094189). The CFARs are
NIH funded programs which are supported by the following
NIH Co-Funding and Participating Institutes and Centers:
NIGMS, NIDDK, and OAR. The content of this paper is
solely the responsibility of the authors and does not
necessarily represent the ofcial views of the NIH.
The authors would like to express gratitude to the
Baltimore Department of Health and Mental Hygiene, the
Philadelphia Department of Public Health, the Baltimore
City Syringe Exchange program, and Prevention Point
Philadelphia. We would also like to thank Danielle Fiore
for her assistance with the abstraction of the Philadelphia
surveillance data.
L.S.W. is currently a Visiting Professor of Health
Policy and Management and Distinguished Fellow in the
Fitzhugh Mullan Institute for Health Workforce Equity at the
Milken Institute School of Public Health, George Washington
university. D.R.H. is currently the Dean and SUNY Empire
Innovation Professor at the University of Albany, State
University of New York (SUNY). C.P.C. is currently retired
from the Baltimore City Health Department.
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... • fund and expand legal access to "harm-reduction" programs intended to decrease the number of drugrelated deaths and communicable diseases via the: (a) medical supervision of the use of dangerous drugs so that medics can administer life-saving treatment when overdoses occur, (b) distribution of overdose reversal kits that drug-users can take home, (c) testing of drugs to ensure that there are not any unknown impurities or alternative substances like fentanyl mixed into the substances being consumed, (d) distribution of clean needles (in order to reduce viral/bacterial infections due to the use of unclean needles for syringe-injected drugs), (e) promote outreach for drug-addicted individuals in order to provide education about safe(r) drug-use practices and encourage needed treatment and (f) provide vaccinations against diseases that are commonly contracted via the use of injectable drugs 133 . Prior research has indicated that harm-reduction programs like safe-injection sites and clean needle exchange programs reduce drug-related deaths and disease infections 134,135 , and ...
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This report presents research that has identified the ways that mental health and mental health treatment has changed during the COVID-19 pandemic for New Jersey residents and how such changes compare to those observed nationally and worldwide. This study investigated this topic via three main methods: (1) analysis of the results of an original poll we designed and administered in March-April 2023 asking a sample of New Jersey residents to report their mental health and mental health treatment experiences during the COVID-19 pandemic, (2) analysis of publicly available datasets that contain New Jersey-specific information relevant to the study of mental health and mental health treatment that allow for comparisons between pre-pandemic and pandemic time periods and (3) a review of relevant published research.
... Ruiz et al. [51] present strategies to address the barriers to implementing community-based disease prevention programs and identify the main barriers to their success as being issues of scale and complexity, an adaptation of the model to a "community" without geopolitical boundaries or infrastructure; linguistic and cultural diversity, and the sustainability of the program in a poor community, among others. For Kottke et al. [52], a system of preventive services needs to systematically determine which patients potentially need the services, must advise such patients that action is indicated, and describe the benefit of the services in terms that are meaningful to the patient, and empower and assist each patient in how to take action. ...
... The fitted model was used to conduct two types of analyses, interrupted time series analyses (ITSA) and forecasting. This analytic approach (ARIMA modelling and ITSA) has been shown to be a useful strategy for assessing the impact of an intervention on time series data [39][40][41]. ITSA was used to evaluate step and slope changes in monthly counts of opioid-involved overdose fatalities following naloxone dispensation at PHVMs. ...
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Introduction Implementing public health vending machines (PHVMs) is an evidence-based strategy for mitigating substance use-associated morbidity and mortality via the dispensation of essential supplies to people who use drugs, including overdose prevention resources. PHVMs have been implemented throughout the world; however, their implementation in the United States (US) is a recent phenomenon. In 2017, Trac-B Exchange (a syringe services program in Clark County, Nevada) installed three PHVMs. In 2019, naloxone dispensation was launched at PHVMs in Clark County. The purpose of this research is to examine the extent to which naloxone dispensation at PHVMs was associated with changes in opioid-involved overdose fatalities.Methods Monthly counts of opioid-involved overdose fatalities among Clark County residents that occurred from January 2015 to December 2020 were used to build an autoregressive integrated moving averages (ARIMA) model to measure the impact of naloxone dispensation at PHVMs. We forecasted the number of expected opioid-involved overdose fatalities had naloxone dispensation at PHVMs not occurred and compared to observed monthly counts. Interrupted time series analyses (ITSA) were used to evaluate the step (i.e. the immediate impact of naloxone dispensation at PHVMs on opioid-involved overdose fatalities) and slope change (i.e. changes in trend and directionality of monthly counts of opioid-involved overdose fatalities following naloxone dispensation at PHVMs).Results During the 12-months immediately following naloxone dispensation at PHVMs, our model forecasted 270 opioid-involved overdose fatalities, but death certificate data indicated only 229 occurred, suggesting an aversion of 41 deaths. ITSA identified a significant negative step change in opioid-involved overdose fatalities at the time naloxone dispensation at PHVMs was launched (B = −8.52, p = .0022) and a significant increasing slope change (B = 1.01, p
Background: The opioid crisis is a public health emergency in the United States, particularly in rural Pennsylvania. Stigma in rural communities is a treatment barrier and impacts harm reduction programming availability.Objectives: The current study utilized an observational, cross-sectional design to examine latent subgroups of stigma and differences in support for harm reduction strategies (i.e., safe injection facilities, syringe services programs, fentanyl test strips, Naloxone distribution). Participants included rural Pennsylvanians (n = 252), taken from a statewide survey of opioid use disorder (OUD) stigma. Participants reported OUD public stigma (i.e., attitudes/perceptions about OUD, willingness to engage with individuals with OUD) and support for harm reduction strategies.Results: Latent class analysis identified 4 stigma classes: 1) high stigma (HS), 2) high judgment/low stigmatizing behavior (HJ/LB), 3) high stigmatizing behavior/low stigmatizing attitude (HB/LA), and 4) low stigma (LS). ANCOVAs identified subgroup differences in harm reduction support. The HS group indicated less support for safe injection sites, syringe services programs, and fentanyl test strips, compared to the HB/LA and LS groups. The HS group indicated less support for Naloxone distribution compared to the HJ/LB, HB/LA, and LS groups. Lastly, the HJ/LB group indicated less support for each program compared to the LS group.Conclusions/Importance: Findings highlight that OUD stigma profiles differ across rural Pennsylvania and are associated with varying support for harm reduction strategies. Individuals with less stigma report more support for harm reduction strategies. Interventions to implement harm reduction strategies should consider varying levels of stigma and use a targeted approach to inform implementation and messaging strategies.
The use of controlled substances (narcotics and psychotropic substances) poses increased risks for minors. However, minors are generally excluded from existing harm reduction services (e.g. drug consumption rooms, drug checking, exchange of consumption material). Based on public health considerations, the authors recommend the establishment of harm reduction services for minors.
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Background Receptive injection equipment sharing (i.e., injecting with syringes, cookers, rinse water previously used by another person) plays a central role in the transmission of infectious diseases (e.g., HIV, viral hepatitis) among people who inject drugs. Better understanding these behaviors in the context of COVID-19 may afford insights about potential intervention opportunities in future health crises. Objective This study examines factors associated with receptive injection equipment sharing among people who inject drugs in the context of COVID-19. Methods From August 2020 to January 2021, people who inject drugs were recruited from 22 substance use disorder treatment programs and harm reduction service providers in nine states and the District of Columbia to complete a survey that ascertained how the COVID-19 pandemic affected substance use behaviors. We used logistic regression to identify factors associated with people who inject drugs having recently engaged in receptive injection equipment sharing. Results One in four people who inject drugs in our sample reported having engaged in receptive injection equipment sharing in the past month. Factors associated with greater odds of receptive injection equipment sharing included: having a high school education or equivalent (adjusted odds ratio [aOR] = 2.14, 95% confidence interval [95% CI] 1.24, 3.69), experiencing hunger at least weekly (aOR = 1.89, 95% CI 1.01, 3.56), and number of drugs injected (aOR = 1.15, 95% CI 1.02, 1.30). Older age (aOR = 0.97, 95% CI 0.94, 1.00) and living in a non-metropolitan area (aOR = 0.43, 95% CI 0.18, 1.02) were marginally associated with decreased odds of receptive injection equipment sharing. Conclusions Receptive injection equipment sharing was relatively common among our sample during the early months of the COVID-19 pandemic. Our findings contribute to existing literature that examines receptive injection equipment sharing by demonstrating that this behavior was associated with factors identified in similar research that occurred before COVID. Eliminating high-risk injection practices among people who inject drugs requires investments in low-threshold and evidence-based services that ensure persons have access to sterile injection equipment.
Despite substantial advances in the field, liver disease morbidity and mortality remain serious issues among people with HIV. The causes of liver disease are often multifactorial and include hepatitis viruses, hepatic steatosis and oxidative stress, bacterial translocation with activation of hepatic macrophages and stellate cells, and direct toxicities from alcohol and drugs of abuse. Biopsychosocial factors including a high prevalence of psychiatric disorders, food insecurity, insufficient access to care and medications, and social stigma all play roles in the persistence of liver injury and hepatic fibrosis development among people with HIV. Rising rates of hepatocellular carcinoma have been observed, suggesting that the epidemiology of liver disease is evolving.
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Background: Existing research in urban areas has documented a multitude of ways in which law enforcement may affect risks for bloodborne infectious disease acquisition among people who inject drugs (PWID), such as via syringe confiscation and engaging in practices that deter persons from accessing syringe services programs (SSPs). However, limited work has been conducted to explore how law enforcement may impact SSP implementation and operations in rural counties in the United States. This creates a significant gap in the HIV prevention literature given the volume of non-urban counties in the United States that are vulnerable to injection drug use-associated morbidity and mortality. Objective: This study explores the influence of law enforcement during processes to acquire approvals for SSP implementation and subsequent program operations in rural Kentucky counties. Methods: From August 2020 to October 2020, we conducted eighteen in-depth qualitative interviews among persons involved with SSP implementation in rural counties in Kentucky (USA). Interviews explored the factors that served as barriers and facilitators to SSP implementation and operations, including the role of law enforcement. Results: Participants described scenarios in which rural law enforcement advocated for SSP implementation; however, they also reported police opposing rural SSP implementation and engaging in adverse behaviors (e.g., targeting SSP clients) that may jeopardize the public health of PWID. Participants reported that efforts to educate rural law enforcement about SSPs were particularly impactful when they discussed how SSP implementation may prevent needlestick injuries. Conclusions: The results of this study suggest that there are multiple ways in which rural SSP implementation and subsequent operations in rural Kentucky counties are affected by law enforcement. Future work is needed to explore how to expeditiously engage rural law enforcement, and communities more broadly, about SSPs, their benefits, and public health necessity.
Syringe services programmes face operational challenges to provide life‐sustaining services to people who use substances and those who have substance use disorders. COVID‐19 has disrupted operations at these programmes and is a threat to people with substance use disorder because of severe poverty, de‐prioritisation of COVID‐19 safety and high prevalence of comorbidities. This phenomenological qualitative study describes 16 in‐depth interviews with staff of one of the largest syringe services programme in North America—Prevention Point Philadelphia, located in the Kensington neighbourhood of Philadelphia, Pennsylvania. Interviews were conducted from December 2020 to February 2021, audio‐recorded, transcribed and coded to develop a thematic framework. Participants were mostly white (71.4%) and female (68.8%) with a median age of 31.5. Three main and four sub‐themes related to the impact of COVID‐19 on the syringe services programme were identified: (1) COVID‐19 altered services provision (sub‐theme: select service changes should be retained); (2) unclear or absent COVID‐19 response guidance which compromised mitigation (sub‐themes: COVID‐19 messaging was difficult to translate to practice, learn‐as‐we‐go); and (3) staff and clients experienced elevated mental anguish during the pandemic (sub‐theme: already limited resources were further strained). COVID‐19 presented complex challenges to an organisation normally strained in pre‐pandemic times. A staff culture of resourcefulness and resiliency aided the syringe services programme to balance client needs and staff safety. However, staff experienced a serious psychological impact, largely attributable to being unable to find reprieve from the stressors of COVID‐19 and the difficulties associated with navigating and acting‐on contradictory public health messaging. Staff also shared a belief that the relaxing of some pre‐pandemic barriers allowed staff to link clients more readily with services. Syringe services programmes should embrace the potential for lasting changes to health services delivery brought about by wide‐scale changes in service provisions because of COVID‐19.
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Background: The dynamics of injection drug use and higher-risk sexual practices compound the risk of HIV and HCV acquisition. Published literature on people who inject drugs (PWID) has examined risk of infection assuming homogeneity of cohort behavior. Categorizing subgroups by injection and sexual risk can inform a more equitable approach to how syringe services programs (SSPs) adapt harm reduction resources and implementation of evidence-based interventions. We explored injection and sexual risk profiles among PWID to determine significant predictors of class membership. Methods: Data were collected from 1,272 participants at an SSP in Miami-Dade County. Latent Class Analysis (LCA) examined how 10 injection/sexual behavior indicators cluster together to create profiles. Model fit statistics and multivariable multinomial latent class regression identified the optimal class structure and significant predictors of class membership. We assessed SSP visits, naloxone access, HIV/HCV testing and prevalence, and incidence of self-reported wounds. Results: Three distinct profiles of injection/sexual risk were determined: Low Injection/High Sexual (LIHS) (9.4%); High Injection/Moderate Sexual (HIMS) (18.9%); and Low Injection/Low Sexual (LILS) (71.7%). Participants reporting gay/bisexual orientation and methamphetamine injection more likely belonged to the LIHS class. LIHS class members had higher prevalence of HIV, while those of HIMS reported increased hepatitis C prevalence. Compared to members of LILS, those of HIMS more likely experienced unstable housing, gay/bisexual orientation, heroin or speedball injection, and identifying as women. HIMS cohort members had more SSP visits, naloxone accessed, and higher wound incidence than those of LILS. Conclusions: Understanding PWID subgroups amplifies the importance of implementing evidencebased interventions such as PrEP for those engaging in highest risk behavior, with focused interventions of antiretroviral management and access to condoms for members of the LIHS class and HCV screening with wound care for those belonging to HIMS.
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This study examines trends of injection drug users' (IDUs) use of a Philadelphia, Pennsylvania, syringe exchange program (SEP) from 1999 to 2014, including changes in demographics, drug use, substance abuse treatment, geographic indicators, and SEP use. Prevention Point Philadelphia's SEP registration data were analyzed using linear regression, Pearson's Chi square, and t-tests. Over time new SEP registrants have become younger, more racially diverse, and geographically more concentrated in specific areas of the city, corresponding to urban demographic shifts. The number of new registrants per year has decreased, however syringes exchanged have increased. Gentrification, cultural norms, and changes in risk perception are believed to have contributed to the changes in SEP registration. Demographic changes indicate outreach strategies for IDUs may need adjusting to address unique barriers for younger, more racially diverse users. Implications for SEPs are discussed, including policy and continued ability to address current public health threats.
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Syringe exchange programs (SEPs) lower HIV risk. From 1998 to 2007, Congress prohibited Washington, DC, from using municipal revenue for SEPs. We examined the impact of policy change on IDU-associated HIV cases. We used surveillance data for new IDU-associated HIV cases between September 1996 and December 2011 to build an ARIMA model and forecasted the expected number of IDU-associated cases in the 24 months following policy change. Interrupted time series analyses (ITSA) were used to assess epidemic impact of policy change. There were 176 IDU-associated HIV cases in the 2 years post-policy change; our model predicted 296 IDU-associated HIV cases had the policy remained in place, yielding a difference of 120 averted HIV cases. ITSA identified significant immediate (B = -6.0355, p = .0005) and slope changes (B = -.1241, p = .0427) attributed to policy change. Policy change is an effective structural intervention for HIV prevention when it facilitates the implementation of services needed by vulnerable populations.
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Background: A breadth of literature exists that explores the utilization of research evidence in policy change processes. From this work, a number of studies suggest research evidence is applied to change processes by policy change stakeholders primarily through instrumental, conceptual, and/or symbolic applications, or is not used at all. Despite the expansiveness of research on policy change processes, a deficit exists in understanding the role of research evidence during change processes related to the implementation of structural interventions for HIV prevention among injection drug users (IDU). This study examined the role of research evidence in policy change processes for the implementation of publicly funded syringe exchange services in three US cities: Baltimore, MD, Philadelphia, PA, and Washington, DC. Methods: In-depth qualitative interviews were conducted with key stakeholders (n=29) from each of the study cities. Stakeholders were asked about the historical, social, political, and scientific contexts in their city during the policy change process. Interviews were transcribed and analyzed for common themes pertaining to applications of research evidence. Results: In Baltimore and Philadelphia, the typological approaches (instrumental and symbolic/conceptual, respectively) to the applications of research evidence used by harm reduction proponents contributed to the momentum for securing policy change for the implementation of syringe exchange services. Applications of research evidence were less successful in DC because policymakers had differing ideas about the implications of syringe exchange program implementation and because opponents of policy change used evidence incorrectly or not at all in policy change discussions. Conclusion: Typological applications of research evidence are useful for understanding policy change processes, but their efficacy falls short when sociopolitical factors complicate legislative processes. Advocates for harm reduction may benefit from understanding how to effectively integrate research evidence into policy change processes in ways that confront the myriad of factors that influence policy change.
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Enhanced HIV prevention interventions, such as preexposure prophylaxis for high-risk individuals, require substantial investments. We sought to estimate the medical cost saved by averting 1 HIV infection in the United States. We estimated lifetime medical costs in persons with and without HIV to determine the cost saved by preventing 1 HIV infection. We used a computer simulation model of HIV disease and treatment (CEPAC) to project CD4 cell count, antiretroviral treatment status, and mortality after HIV infection. Annual medical cost estimates for HIV-infected persons, adjusted for age, sex, race/ethnicity, and transmission risk group, were from the HIV Research Network (range, $1854-$4545/mo) and for HIV-uninfected persons were from the Medical Expenditure Panel Survey (range, $73-$628/mo). Results are reported as lifetime medical costs from the US health system perspective discounted at 3% (2012 USD). The estimated discounted lifetime cost for persons who become HIV infected at age 35 is $326,500 (60% for antiretroviral medications, 15% for other medications, 25% nondrug costs). For individuals who remain uninfected but at high risk for infection, the discounted lifetime cost estimate is $96,700. The medical cost saved by avoiding 1 HIV infection is $229,800. The cost saved would reach $338,400 if all HIV-infected individuals presented early and remained in care. Cost savings are higher taking into account secondary infections avoided and lower if HIV infections are temporarily delayed rather than permanently avoided. The economic value of HIV prevention in the United States is substantial given the high cost of HIV disease treatment.
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We assessed the effects of syringe exchange program (SEP) policy on rates of HIV risk behavior and HIV incidence among injection drug users. Using a multivariate generalized estimating equation and Cox regression methods, we examined syringe borrowing, syringe lending, and HIV incidence among a prospective cohort of 1228 injection drug users in Vancouver, British Columbia. We observed substantial declines in rates of syringe borrowing (from 20.1% in 1998 to 9.2% in 2003) and syringe lending (from 19.1% in 1998 to 6.8% in 2003) following SEP policy change. These declines coincided with a statistically significant increase in the proportion of participants accessing sterile syringes from nontraditional SEP sources (P < .001). In multivariate analyses, the period following the change in SEP policy was independently associated with a greater than 40% reduction in syringe borrowing (adjusted odds ratio [AOR] = 0.57; 95% confidence interval [CI] = 0.49, 0.65) and lending (AOR = 0.52; 95% CI = 0.45, 0.60), as well as declining HIV incidence (adjusted hazard ratio = 0.13; 95% CI = 0.06, 0.31). Widespread syringe distribution appears to be a more effective SEP policy than do more restrictive SEP policies that limit syringe access. Efforts should be made to ensure that SEP policies and program design serve to maximize rather than hinder syringe access.
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This case-control study examined the association between syringe exchange use and hepatitis B and C in injection drug users. Case patients included 28 injection drug users with acute hepatitis B and 20 with acute hepatitis C reported to the health department in a sentinel hepatitis surveillance county; control subjects were injection drug users with no markers of exposure to hepatitis B or C (n = 38 and 26, respectively) attending health department services during the same period. Data were abstracted from clinic records. Seventy-five percent of case patients with hepatitis B and 26% of control subjects had never used the exchange; similar proportions were found for the hepatitis C case and control groups. After adjustment for demographic characteristics and duration of injecting drugs, nonuse of the exchange was associated with a sixfold greater risk of hepatitis B (odds ratio [OR] = 5.5; 95% confidence interval [CI] = 1.5, 20.4) and a sevenfold greater risk of hepatitis C (OR = 7.3; 95% CI = 1.6, 32.8). The results suggest that use of the exchange led to a significant reduction in hepatitis B and hepatitis C in the county and may have also prevented a substantial proportion of human immunodeficiency virus infections in injection drug users.
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There have been no studies showing that participation in programmes which provide legal access to drug-injection equipment leads to individual-level protection against incident HIV infection. We have compared HIV incidence among injecting drug users participating in syringe-exchange programmes in New York City with that among non-participants. We used meta-analytic techniques to combine HIV incidence data from injecting drug users in three studies: the Syringe Exchange Evaluation (n = 280), in which multiple interviews and saliva samples were collected from participants at exchange sites; the Vaccine Preparedness initiative cohort (n = 133 continuing exchanges and 188 non-exchangers, in which participants were interviewed and tested for HIV every 3 months; and very-high-seroprevalence cities in the National AIDS Demonstration Research (NADR) programme (n = 1029), in which street-recruited individuals were interviewed and tested for HIV every 6 months. In practice, participants in the NADR study had not used syringe exchanges. HIV incidence among continuing exchange-users in the Syringe Exchange Evaluation was 1.58 per 100 person-years at risk (95% CI 0.54, 4.65) and among continuing exchange-users in the Vaccine Preparedness Initiative it was 1.38 per 100 person-years at risk (0.23, 4.57). Incidence among non-users of the exchange in the Vaccine Preparedness Initiative was 5.26 per 100 person-years at risk (2.41, 11.49), and in the NADR cities, 6.23 per 100 person-years at risk (4.4, 8.6). In a pooled-data, multivariate proportional-hazards analysis, not using the exchanges was associated with a hazard ratio of 3.35 (95% CI 1.29, 8.65) for incident HIV infection compared with using the exchanges. We observed an individual-level protective effect against HIV infection associated with participation in a syringe-exchange programme. Sterile injection equipment should be legally provided to reduce the risk of HIV infection in persons who inject illicit drugs.
To review the evidence on the effectiveness of harm reduction interventions involving the provision of sterile injecting equipment in the prevention of hepatitis C virus (HCV) and human immunodeficiency virus (HIV) transmission among injecting drug users (IDUs). The interventions assessed were needle and syringe programmes (NSP), alternative modes of needle/syringe provision (pharmacies, vending machines and outreach) and the provision of injecting equipment other than needles/syringes. Systematic searches of the English language literature to March 2007 were undertaken to identify systematic, narrative or meta-analytical reviews (also known as a review of reviews) of the impact of interventions on HCV transmission, HIV transmission or injecting risk behaviour (IRB). Critical appraisal criteria classified the reviews as either high quality ('core') or supplementary: a framework based on the quality of reviews, the reviewers' conclusions and the designs/findings of the primary studies was used to derive evidence statements. Three core and two supplementary reviews of injecting equipment interventions were identified. According to the proposed framework, this study found (a) insufficient evidence to conclude that any of the interventions are effective in preventing HCV transmission; (b) tentative evidence to support the effectiveness of NSP in preventing HIV transmission; (c) sufficient evidence to support the effectiveness of NSP (and tentative evidence of an additional impact of pharmacy NSP) in reducing self-reported IRB; and (d) little to no evidence on vending machines, outreach or providing other injecting equipment in relation to any of the outcomes. The evidence is weaker than given credit for in the literature. The lack of evidence for effectiveness of NSP vis-à-vis biological outcomes (HCV and HIV incidence/prevalence) reflects the limitations of studies that have been undertaken to investigate these associations. Particularly for HCV, low levels of IRB may be insufficient to reduce high levels of transmission. New studies are required to identify the intervention coverage necessary to achieve sustained changes in blood-borne virus transmission.
The legal needle exchange in New Haven, Connecticut, was signed into law in July 1990. As part of a rigorous effort to evaluate this program, all distributed syringes receive unique tracking codes, and a sample of returned needles are tested for the presence of HIV proviral DNA via polymerase chain reaction. These data, in conjunction with "back-of-the-envelope" statistical models, allow the estimation of HIV prevalence among those intravenous drug users participating in the needle exchange. We present four new techniques for calculating prevalence estimates: the majority rule cutoff model, the random sharing model, the sharing network model, and a version of Kaplan's "needles that kill" model. To our knowledge, these estimates are the first that attempt to infer HIV prevalence among intravenous drug users via syringe tracking and testing. All four techniques suggest a prevalence of infection of approximately 60%.