Needle exchange and difficulty with needle access during an ongoingHIV epidemic

Evan Wood a,b, Mark W. Tyndall a,b, Patricia M. Spittal a,b, Kathy Li a, RobertS. Hogg a,b, Michael V. O’Shaughnessy a,c, Martin T. Schechter a,b,*

a British Columbia Centre for Excellence in HIV/AIDS, St. Paul’s Hospital, Vancouver, BC, Canadab Department of Health Care and Epidemiology, University of British Columbia, 5804 Fairview Ave., Vancouver, BC, Canada V6T 1Z3

c Department of Pathology and Laboratory Medicine; University of British Columbia, Vancouver, BC, Canada

Abstract

During the mid to late 1990s, Vancouver, Canada experienced a rapid injection drug use-related HIV epidemic, despite the

presence of a well-established, high-volume, needle exchange program (NEP). The NEP presently exchanges needles through several

fixed sites, the largest of which operates in the city’s Downtown Eastside where injection drug users (IDU) are concentrated, and

through mobile exchange vans which exchange needles throughout neighboring areas. The program’s inability to prevent the

epidemic has led to persistent questions about the efficacy of needle exchange as a public health intervention. We recently sought

possible explanations for persistent needle sharing through an evaluation of the Vancouver Injection Drug Users Study (VIDUS), an

ongoing cohort study of IDU that began in 1996. In these analyses, the strongest predictor of needle sharing was difficulty accessing

needles; those who reported difficulty accessing needles were 3.5 times more likely to report sharing than those who did not have

difficulty with access. In the present study, we sought to identify reasons why IDU continued to have difficulty accessing needles

despite the efforts of the NEP. Overall, 761 active injectors were interviewed during the period June 2000�/May 2001. Of these 172

(22.6%) reported having difficulty accessing sterile needles. In a multivariate analysis, frequent cocaine injection and bingeing were

associated with difficulty accessing needles, whereas residing in the Downtown Eastside was negatively associated with difficulty.

When we evaluated IDU’s reasons for difficulty with access, the most common reasons given were the operating hours of the NEP,

difficulty meeting the needle exchange van, being away from the area where needles are exchanged, and being refused sterile needles

at pharmacies. These findings suggest that programmatic deficiencies related to the operation of the needle exchange and refusal of

pharmacists to sell needles may be primary factors related to difficulty accessing needles. # 2002 Elsevier Science B.V. All rights

reserved.

Keywords: HIV; AIDS; Needle exchange; Injection drug users; Harm reduction; Vancouver

Introduction

Studies have shown that providing injection drug

users (IDUs) access to clean needles through needle

exchange programs (NEP) substantially reduces the

transmission of HIV as well as HIV risk behaviors

(Bluthenthal, Kral, Gee, Erringer & Edlin, 2000; Des

Jarlais et al., 1996). Furthermore, needle exchange has

been shown to afford a crucial opportunity to reach

drug users and provide them with additional resources

such as HIV testing and counseling and referrals to drug

treatment (Heimer, 1998; Lurie, Reingold & Bowser,

1993; Strathdee et al., 1999).

However, NEPs remain a controversial intervention

in many countries. Opponents argue that NEPs enable

drug use, are not effective at reducing HIV transmission,

and may even promote its spread (American Journal of

Public Health, 2000Bellm, 1999; Bennett, 1998). Debate

over the efficacy of NEPs has been partially fueled by

the experience of Vancouver, Canada (Bellm, 1999;

Schechter et al., 1999). Although the city had in place

a NEP that had been ranked among the top three in

North America in terms of the proportion of drug users

ever reached and needles exchanged (Lurie et al., 1993),

in 1997 an explosive HIV epidemic characterized by an

18% annual incidence rate was observed among IDU

* Corresponding author. Tel.: �/1-604-822-3081; fax: �/1-604-806-

9044.

E-mail address: martin.schechter@ubc.ca (M.T. Schechter).

International Journal of Drug Policy 13 (2002) 95�/102

www.elsevier.com/locate/drugpo

0955-3959/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved.

PII: S 0 9 5 5 - 3 9 5 9 ( 0 2 ) 0 0 0 0 8 - 7

residing in the city’s Downtown Eastside (Strathdee et

al., 1997b). We also observed that the prevalence of

HIV-1 among those who frequently attended the NEP

was higher than among those who attended lessfrequently (Strathdee et al., 1997b). These observations

were interpreted by some to suggest that NEPs may

exacerbate the spread of HIV (Bellm, 1999; Office of

National Drug Control Policy, 1998). Subsequently, we

demonstrated that the association between frequent

NEP attendance and HIV-1 was due to the selection

by NEPs of higher risk drug users (Schechter et al.,

1999). Furthermore, we and others have refuted thehypothesis that NEPs promote the formation of needle

sharing networks (Junge, Valente, Latkin, Riley &

Vlahov, 2000; Schechter et al., 1999).

Since the overwhelming majority of studies have

found a benefit of making sterile needles accessible to

IDU, a critical question surrounds the safest and most

effective means of providing this service (Coffin, 2000).

Prescription of syringes, legal pharmacy sales, andneedle exchange have all been evaluated as modes of

making sterile needles accessible to IDU (Cotten-Old-

enburg, Carr, DeBoer, Collison & Novotny, 2001; Rich,

Macalino, McKenzie, Taylor & Burris, 2001; Singer et

al., 2000). While in some settings, legal barriers have

limited the accessibility of syringes to IDU, in other

settings operational or structural barriers such as

geographic accessibility must also be explored (Case,Meehan & Jones, 1998; Rockwell, Des Jarlais, Fried-

man, Perlis & Paone, 1999).

Over the last few years, further efforts have been

made to expand access to clean needles in Vancouver.

The number of needles exchanged was over 3 million in

the year 2000 (City of Vancouver, 2000). The exchange

program serves the city’s approximately 5000�/10 000

IDU, and augments the pharmacy sale of needles, whichis legal in Canada (Health Canada, 1998; Royal

Canadian Mounted Police, 2000). The NEP operates

through a number of fixed site needle exchanges in the

Downtown Eastside, several of which are within the

neighborhood’s low-income hotels, as well as through

mobile exchange vans, which exchange needles through-

out the night (Schechter et al., 1998; City of Vancouver,

2000). The exchange vans also exchange syringes inneighboring areas where syringe exchanges do not exist,

and several small syringe exchange programs operate in

municipalities surrounding Vancouver. IDU are in-

formed about the locations of needle exchanges and

the exchange vans through advertisements and flyers at

the fixed sites and at other services for IDU, as well as

through word of mouth. Despite these efforts, the

continuing transmission of HIV and HCV suggeststhat high numbers of IDUs continue to share needles

(Patrick et al., 2000).

Most recently, we have shown that persons who

obtain needles exclusively from needle exchange were

half as likely to share needles than persons who acquired

their needles from other sources (Wood, Tyndall,

Spittal, Li, O’Shaughnessy & Schechter, 2001a). How-

ever, these analyses also identified several risk factorsthat may explain persistent high-risk needle sharing in

Vancouver. The risk factor most strongly associated

with needle sharing was reporting having difficulty

accessing needles. Those who reported difficulty with

accessing sterile needles were 3.5 times more likely to

report needle sharing than persons who did not report

having difficulty with access (Wood et al., 2001a). This

observation raises several questions about why IDUs inVancouver continue to have difficulty accessing sterile

injecting equipment despite the high volume of needles

exchanged through the large exchange program. There-

fore, the present study was conducted to evaluate

reasons for difficulty accessing needles among Vancou-

ver IDUs.

Methods

Beginning in May 1996, persons who had injected

illicit drugs in the previous month were recruited into

the Vancouver Injection Drug User Study (VIDUS).

Data collection for the project is conducted in a

storefront office. The study site is not connected to,

and operates independently of, the NEP. Over 1400study subjects were recruited through self-referral and

street outreach. Persons were eligible if they had injected

illicit drugs at least once in the previous month, resided

in the greater Vancouver region, and provided written

informed consent. Ethical approval for the project was

provided by the University of British Columbia. Evi-

dence of recent injection drug use was required by

inspection of needle tracks. At baseline and semi-annually, subjects provided blood samples and com-

pleted an interviewer-administered questionnaire. The

questionnaire elicits demographic data including age,

gender, and place of residence, as well as drug use, risk

behaviors, and attendance at drug treatment and needle

exchanges. Participants are provided a nominal mone-

tary stipend at each study visit.

For the purposes of this study, we restricted ouranalyses to persons who returned for follow-up during

the period June 1, 2000�/May 31, 2001. Persons who had

not injected drugs in the previous 6 months were

excluded from all analyses since we sought to evaluate

reasons for difficulty accessing needles among persons

who were actively injecting drugs.

In order to identify IDU that are having difficulty

accessing syringes, the following question was asked ofall current injectors at their most recent follow-up:

‘‘Right now, do you currently find it hard to get new

rigs [needles ] when you need them?’’.

E. Wood et al. / International Journal of Drug Policy 13 (2002) 95�/10296

Participants were then offered to answer either Yes,

No, or Sometimes. We defined a person as ‘having

difficulty accessing needles’ if they answered yes or

sometimes to this question.We then sought to derive a socio-demographic and

drug using profile of persons who had difficulty acces-

sing syringes. Demographic characteristics such as age,

gender, and ethnic background were derived from the

baseline questionnaire. In order to evaluate current

activities, behavioral characteristics such as drug use,

and health-related characteristics such as HIV infection

were derived from the participant’s most recent follow-up questionnaire during the study period. Drug using

variables considered included frequency of cocaine and

heroin injection, and bingeing. Persons who reported

injecting cocaine or heroin once or more per day were

defined as frequent cocaine and frequent heroin users,

respectively. Bingeing was defined as binges or runs

where drugs were injected more frequently than usual.

Statistical analyses were applied to compare personswho had difficulty with access to participants who did

not have difficulty with access in the last 6 months.

Categorical explanatory variables were analyzed using

Pearson’s x2-test and continuous variables were ana-

lyzed using the Wilcoxon rank sum test. All variables

that were statistically significant at the 0.05 cut-off were

considered in logistic regression analyses.

For all persons who reported having difficulty acces-sing needles, the following question was then asked: ‘‘If

yes or sometimes, why do you find it hard to get new

[unused ] rigs?’’.

The interviewer did not read out a list of possible

explanations, but had a list of nine possible responses,

which were developed through prior piloting of this

question, as well as space to note answers that did not fit

with one of the nine categories. Participants were able toprovide more than one explanation.

In order to evaluate participant responses to the latter

question, the answers of all participants who reported

difficulty with access were summarized. However, in

order to rule out the potential for confounding as a

result of needle exchange source, we stratified the data

so that participants were divided into those who

acquired most (]/75%) of their needles from the fixedsite needle exchanges, the exchange vans, or from

pharmacies. We then evaluated the reasons for difficulty

accessing needles in each of the three groups.

Results

Overall, 942 participants returned for follow-up

during the period June 1, 2000�/May 31, 2001. Sincethe study’s inception, 124 participants have died. A

linkage with the province’s Vital Statistics Agency

indicated that deaths were due to HIV/AIDS (23%),

overdoses (33%), and other causes such as hepatitis and

suicides (44%). In addition, there were 371 participants

who did not come in for the most recent follow-up. Of

the 942 participants who were followed during the studyperiod, 761 (81%) reported injecting drugs in the last 6

months and were, therefore, included in the present

study. Of the 761 participants who were identified as

active IDU, 589 (77%) did not report having difficulty

accessing needles in the last 6 months, whereas 172

(23%) reported difficulty.

Table 1 shows the socio-demographic and drug using

characteristics of the participants stratified by those thatdid and did not have difficulty accessing needles. As

shown here, younger age (P B/0.001), male gender (P�/

0.041), residing outside of the Downtown Eastside (P�/

0.027), having been incarcerated in the last 6 months

(P�/0.003), using cocaine frequently (P�/0.001), using

heroin frequently (P�/0.001), and bingeing (P�/0.003)

were associated with difficulty accessing needles. We

found no association between difficulty accessing nee-

Table 1

Univariate analyses comparing socio-demographic characteristics of

persons who did and did not report having difficulty accessing needles

Characteristic Difficulty assessing rigs?

No n (%) Yes n (%) P -value

Age

Median 39 34 B0.001

IQR 32�/45 28�/41

Gender

Female 366 (62.1) 92 (53.5) 0.041

Male 223 (37.9) 80 (46.5)

Ethnic background

Aboriginal 167 (28.4) 53 (30.8) 0.531

Other 422 (71.7) 119 (69.2)

HIV positive

No 393 (66.7) 119 (69.2) 0.545

Yes 196 (33.3) 53 (30.8)

Neighborhood residence

Other 222 (37.7) 81 (47.1) 0.027

Downtown Eastside 367 (62.3) 91 (52.9)

Unstable housing

No 278 (47.2) 72 (41.9) 0.217

Yes 311 (52.8) 100 (58.1)

Incarcerated in the last 6 months

No 471 (80.0) 119 (69.2) 0.003

Yes 118 (20.0) 53 (30.8)

Heroin use frequency

B1 per day 442 (75.0) 103 (59.9) 0.001

]1 per day 147 (25.0) 69 (40.1)

Cocaine use frequency

B1 per day 504 (85.6) 125 (72.7) 0.001

]1 per day 85 (14.4) 47 (27.3)

Bingeing

No 420 (71.3) 102 (59.3) 0.003

Yes 169 (28.7) 70 (40.7)

E. Wood et al. / International Journal of Drug Policy 13 (2002) 95�/102 97

dles and ethnic background, HIV sero-status, or hous-

ing. Overall, 142 (18.7%) participants injected approxi-

mately once per month, 338 (44.4%) injected less than

once per day, 114 (15.0%) injected one to three times per

day, 61 (8.0%) injected three to five times per day, 106

(13.9%) injected greater than five times per day.

Table 2 shows the logistic regression analysis of

factors associated with difficulty accessing needles. As

shown here, older age (adjusted odds ratio [AOR]�/0.95

per year) and Downtown Eastside residence (AOR�/

0.56) were associated with less difficulty, whereas

frequent cocaine injection (AOR�/2.20) and bingeing

(AOR�/1.63) were associated with greater difficulty

accessing syringes. When this analysis was stratified by

where persons acquired most of their sterile needles

(either fixed site, van, or pharmacy) we found similar

results. The only noteworthy difference between the

overall model and the stratified analyses was that living

in the Downtown Eastside was only significant for fixed

site users (AOR�/0.51), whereas this variable was not

significant for van users and pharmacy users in stratified

multivariate analyses.

Fig. 1. Frequency of responses to the question regarding why participants had difficulty accessing sterile needles among the 69 participants who

acquired most of their needles from the fixed site exchanges.

Fig. 2. Frequency of responses to the question regarding why participants had difficulty accessing sterile needles among the 33 participants who

acquired most of their needles from the exchange vans.

Table 2

Logistic regression analysisa of factors associated with difficulty

accessing sterile syringes

Variable Adjusted odds

ratio

95% Confidence

interval

Age (per year older) 0.95 (0.93�/0.97)

Downtown Eastside residence

(yes vs. no)

0.56 (0.39�/0.82)

Cocaine use frequency (]1

daily daily vs. B1)

2.20 (1.14�/3.43)

Bingeing (yes vs. no) 1.63 (1.11�/2.37)

a Variables that were statistically significant at the 0.05 cut-off were

considered in the model.

E. Wood et al. / International Journal of Drug Policy 13 (2002) 95�/10298

Overall, 351 (46.1%) of participants acquired most of

their needles from the fixed site exchanges, 109 (14.3%)

from the exchange vans, 60 (7.9%) from pharmacies,

and 241 (31.7%) acquired needles from multiple sourcesand did not identify a primary source. Of the 351

participants who acquired most of their needles from a

fixed site needle exchange, 69 (19.7%) also reported

difficulty with needle access. Fig. 1 depicts the reasons

given for this difficulty restricted to these 69 subjects. As

shown here, 49 (71.0%) of these individuals cited the

NEP being closed, 25 (36.2%) cited missing the exchange

van, and 22 (31.9%) cited being out of the area whereNEP operate as the primary reasons for difficulty having

access to sterile needles.

Fig. 2 provides analogous information for the 33

participants who acquired most of their needles from the

exchange vans and also reported difficulty with access.

As shown here, 19 (57.6%) of participants cited missing

the exchange van, 17 (51.5%) cited the NEP being

closed, ten (30.3%) cited being incarcerated, and seven(21.2%) cited being out of the area where NEP operate

as the primary reasons for difficulty having access to

sterile needles.

Similarly, Fig. 3 shows the same information for those

16 participants who acquired most of their needles from

pharmacies and also reported difficulty with access. As

shown here, 11 (68.8%) cited being refused needles at

pharmacies, 11 (68.8%) cited being out of the area whereNEP operate, and eight (50.0%) cited the NEP being

closed as the primary reasons for difficulty having access

to sterile needles.

Discussion

Previously, we identified several risk factors for high-

risk syringe sharing in Vancouver (Wood et al., 2001a).These factors included: bingeing, frequent cocaine

injection, male gender, and difficulty accessing needles

as the primary risk factor for high-risk needle sharing in

Vancouver. While the demographic and drug use factors

carried a relative risk of syringe sharing on the order of

approximately 2.0, persons who reported difficulty with

access to sterile needles were approximately 3.5 times

more likely to report syringe sharing after adjustmentfor other measured confounders. In the present study,

we found that several demographic and drug use

characteristics such as younger age, frequent injection,

bingeing, and living farther away from where exchange

services are concentrated to be associated with difficulty

accessing needles. In addition, the present study pro-

vides additional insight into why IDUs may be having

difficulty accessing needles through an assessment ofIDU’s explanations. Although problems with needle

access varied by needle source, several common themes

emerged. Specifically, the primary reasons for difficulty

accessing needles reported were the NEP being closed,

difficulty meeting the exchange van, being refused

needles at pharmacies, and being incarcerated in the

last 6 months.In previous analyses we have shown that frequent

cocaine injection and bingeing are associated with

needle sharing (Wood et al., 2001a). It is, therefore,

not surprising that these factors were in turn associated

with difficulty accessing needles, given the strong

association between difficulty accessing needles and

needle sharing. It is noteworthy, however, that neither

‘being too high’ nor bingeing emerged as common self-reported explanations for difficulty accessing needles.

This would suggest that bingeing and frequent drug use

may be associated with higher needle requirements, but

that structural barriers to sterile needle acquisition

contribute sharing behavior rather than merely the

instability of high intensity drug users.

Needle exchange operators face numerous challenges

in providing services for IDUs. In many settings,including Vancouver, needle exchanges face community

opposition as well as funding constraints. One way to

appease community concerns has been to offer restricted

hours of service. The operating hours of the Downtown

Eastside’s large fixed site needle exchange were from

8:00am to 8:00pm during the study period. Although it

may be perceived that these hours help to prevent drug

users coming into the area of the exchange during theevening, the present study identified restricted operating

hours as a primary reason for difficulty accessing

needles among all groups, even when the exchange

vans continue to operate. Similarly, funding limitations

may also force exchanges to provide only limited hours

of operation. In Vancouver, during the emergence of the

HIV epidemic, budgetary restrictions resulted in limiting

the services of the mobile exchange vans (Schechter etal., 1998). Although the present study suggests that

needle access would be greatly improved if the operating

hours of the NEP were increased, it is unclear if this

should be done at the expense of the services provided

by the exchange vans. We and others have shown that

mobile exchange vans may provide needle access to a

high-risk population that may not be serviced by fixed

site exchanges alone (Miller et al., 2001; Riley et al.,2000). This would argue for significant extensions of the

operating hours of the fixed site, even at times when the

vans are operating.

It is noteworthy that ‘missing the van’ was cited by a

number of respondents as contributing to their difficulty

in accessing needles. While mobile exchange is known to

expand the reach of NEPs and to access higher risk sub-

populations (Miller et al., 2001), it must be pointed outthat vans only remain in each distant location for a

limited period of time. This could explain the signifi-

cance of ‘missing the van’ as a risk factor. On this basis,

one might argue that an additional mechanism for

E. Wood et al. / International Journal of Drug Policy 13 (2002) 95�/102 99

exchange could be permanent but disseminated sources

of needles throughout high-risk areas. Strategies applied

elsewhere, that should be considered for evaluation in

Vancouver include needle vending machines and perma-

nent safe disposal boxes (Coffin, 2000; Obadia, Feroni,

Perrin, Vlahov & Moatti, 1999).

Needle exchange in the Vancouver region has been

targeted in the Downtown Eastside where IDU are most

highly concentrated, although limited NEPs exist in

some neighboring municipalities and some neighboring

areas are serviced by the exchange vans. Given the

concentration of the NEP’s services, it is not surprising

that being away from locations where needle exchange is

available was associated with difficulty accessing nee-

dles. However, injection drug use is found throughout

urban and rural areas of Canada, and the present study

suggests that novel strategies aimed at making needles

accessible to drug users in areas of low injection drug

use prevalence are needed. One such strategy has been to

legalize the pharmacy sale of needles to IDU. Alar-

mingly, being refused needles at pharmacies was com-

mon among all groups involved in the present study

regardless of their primary source of needles (fixed site,

van, or pharmacy) and was the primary reasons

reported by persons who primarily used pharmacies to

obtain sterile needles. Our findings support previous

analyses that have suggested that an educational cam-

paign directed at pharmacies throughout the province of

British Columbia may be required to help address this

concern (Myers, Cockerill, Worthington, Millson &

Rankin, 1998). In addition, although the present study

suggests that difficulty meeting the exchange van poses

problems, we and others have shown that exchange vans

may be an effective means of providing services to IDUs

in areas of low injection drug use prevalence (Miller et

al., 2001; Riley et al., 2000).

Being incarcerated in the last 6 months was also

identified as a reason for difficulty accessing needles. Of

concern is that we have recently found incarceration to

be independently associated with HIV seroconversion in

our cohort (Tyndall et al., 2001), as has been reported

elsewhere (Taylor et al., 1995). Previous studies have

indicated that injection drugs are widely available in

Canadian prisons, as well as prisons in most other

jurisdictions (Dolan, 2001; Kent, 1996). The present

study adds support to the growing body of literature

which suggests that the potential of NEPs to prevent the

spread of HIV within prisons must be explored,

especially considering the high-risk nature of prison

populations (Rothon, Mathias & Schechter, 1994).

There was little consistency among the ‘other’ answers

where IDUs provided additional explanations for diffi-

culty accessing syringes. It is noteworthy, however, that

several users reported that ‘police presence around the

needle exchange’ made accessing needles difficult, and

an earlier study from our setting identified police

intervention as barrier to sterile needle acquisition

(Strathdee et al., 1997a). To our knowledge, there is

no evidence that either targeted police presence or

incarceration are effective at reducing drug use, and

we have recently argued that legally sanctioned and

supervized safer injecting sites, where addicts can inject

pre-obtained illicit drugs, should be considered for

evaluation in Vancouver (Wood et al., 2001b). Such

facilities could be kept open 24 h and could alleviate

community concerns about drug users being drawn to

public spaces in the evenings, as well as provide space

where drug users could inject safely without fear of

police. Although the present study suggests that im-

proving the operating hours of the NEP may substan-

tially improve needle access, we have previously shown

that bingeing and frequent cocaine injection remain

strongly associated with needle sharing after adjustment

Fig. 3. Frequency of responses to the question regarding why participants had difficulty accessing sterile needles among the 16 participants who

acquired most of their needles from pharmacies.

E. Wood et al. / International Journal of Drug Policy 13 (2002) 95�/102100

for difficulty accessing needles (Wood et al., 2001a).

This observation suggests that merely improving needle

access as an isolated intervention will not be sufficient to

prevent the HIV epidemic in our setting.It is noteworthy that having no needles to exchange

and the NEPs ‘one for one’ exchange policy did not

emerge as common reasons why participants had

difficulty accessing needles. These policies have resulted

in greater than 100% re-acquisition of used needles by

the program, and undoubtedly less contaminated nee-

dles being discarded in public spaces. However, previous

studies have suggested that such policies may beproblematic due to the frequent injection behavior and

instability of cocaine users who are common in Van-

couver (Schechter et al., 1999; Wood et al., 2001a). A

qualitative study of these policies and how they relate to

HIV risk is currently ongoing.

When drawing conclusions from prospective cohort

data, several cautions are warranted. First, while some

studies have shown self-reported HIV risk behavior tobe valid (De Irala, Bigelow, McCusker, Hindin &

Zheng, 1996), other investigations have suggested that

IDUs may under-report HIV risk behavior (Des Jarlais

et al., 1999). Since the questions evaluated in the present

study did not involve HIV risk or other stigmatized

behaviors, it is unlikely that socially desirable reporting

is a major concern in this study.

In summary, our analyses indicate that difficulty inaccessing needles, the primary risk factor for needle

sharing in our setting, is likely related to operational

deficiencies in the NEP. Specifically, the major factors

identified in this study were the restricted operating

hours of the needle exchange and difficulty accessing the

exchange van. In addition, of concern are the reports of

being denied the sale of needles at pharmacies. Purchase

of needles at pharmacies is legal in Canada, and sincebeing away from where a needle exchange operates was

also a common reason for difficulty with access, it is

imperative that IDU have access to needles in areas

where injection drug use may not be prevalent. Finally,

we also identified being incarcerated as an explanation

for difficulty with access. Injection drugs are widely

available in Canadian prisons, and this finding adds to

the widespread consensus that NEPs should be evalu-ated within prisons (Dolan, 2001; Rothon et al., 1994).

Acknowledgements

Evan Wood is supported by Canadian Institutes for

Health Research, and the BC Heath Research Founda-

tion. Dr Schechter holds a tier I Canada Research Chair

in HIV/AIDS and Urban Population Health. The studywas supported by the US National Institutes of Health

(grant no. RO1 DA11591). We thank Bonnie Devlin,

Caitlin Johnston, Robin Brooks, Suzy Coulter, Steve

Kain, Guillermo Fernandez, John Charette, Will Small,

and Nancy Laliberte for their research and adminis-

trative assistance, and all the participants in the VIDUS

study.

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