Table 2 Evidence for key behavioural issues and structural barriers the REACT intervention aims to address

Injecting practices contribute to greater risk of developing bacterial skin and soft tissue infections among people who inject drugs

1. Handwashing/swabbing

Larney et al. [1]

International

Four of six studies conducted in England or the USA reported a reduction in skin infections associated with cleaning injection sites; only one of four studies conducted in England or the USA examining handwashing prior to injection found this behaviour to be significantly associated with reduced skin infections

Vlahov et al. [30]

USA

Of all the persons surveyed, 556/1057 (52.6%) reported cleaning their skin prior to injection at any time and 173/1057 (16.4%) reported cleaning their skin all the time in the 6 months before the interview.

The frequency of subcutaneous abscesses was lower among those who reported skin cleaning all the time; a similar trend was noted for frequency of endocarditis

Murphy et al. [31]

USA

Swabbing the injection site with alcohol before injection was found to have a protective effect against skin and soft tissue abscesses. Significantly fewer people who had developed abscesses, in comparison with controls, had ever used alcohol to clean their skin before drug injection (p < 001)

Dwyer et al. [6]

Australia

Potentially serious or serious injecting-related injuries and disease associated with not always washing hands before injection in the previous 12 months (aOR: 9.3, 2.1–41.8)

Hope et al. [32]

England

Weak evidence that cleaning injection site every time in the last 4 weeks was associated with a reduced prevalence of injection site infection (OR: 0.6, 0.4–0.8)

Stein et al. [17]

USA

60% of participants reported ‘rarely or never’ cleaning their skin before injecting during the past 3 months

2. Use of too much acidifiers

Harris et al. [35]

England

Overuse of acidifiers in injection preparation is common among people who inject drugs in the UK and could play a causative role in venous damage and associated sequelae (skin and soft tissue infection and associated complications).

Associations observed between acidifier overuse, femoral injecting and deep vein thrombosis, but not skin and soft tissue infections. Painful injections and damage to peripheral veins were common and often attributed by participants to the use of citric acid

Ciccarone and Harris [33]

USA and England

Preliminary findings show that different heroin source-forms and preparations have a two-log difference in acidity.

Loss of functioning veins (venous sclerosis) is a root cause of suffering for long-term heroin injectors. In addition to perpetual frustration and loss of pleasure/esteem, venous sclerosis leads to a myriad of medical consequences including skin infections, for example, abscesses

Harris [34]

New Zealand

Opioid injectors in New Zealand using very small amounts of citric acid suffer little vein damage and rarely get skin and soft tissue infections

3. Use of water

Harris et al. [36]

England

Multiple constraints to sourcing sterile water for injection preparation reported.

Participant accounts suggest injection preparation with solvents including puddle water, toilet cistern water, whisky, cola soda and saliva when injecting in public and semi-public spaces. This relates to both behavioural and environmental constraints that increase the risk of infection

Lloyd-Smith et al. [37]

USA

No strong evidence that using a puddle to inject was a risk factor for developing a cutaneous injection-related infection among people who inject drugs (OR 1.32, 0.83–2.11)

Hope et al. [38]

England

Higher levels of reported symptoms of injection site infection associated with reusing water to flush syringes (aOR: 1. 28, 1.03–1.59)

4. Reuse of injecting equipment

Dunleavy et al. [11]

Scotland

Depletion of injecting equipment could lead to reuse of needles, seen as a cause of skin and soft tissue infections by some participants.

Needles were reused because of lack of time or inability to replenish supplies due, for example, to weekend closing of convenient needle and syringe programmes or if they woke in the middle of the night. This relates to structural barriers as well as behavioural barriers

Hope et al. [32]

England

Reporting an injection site infection was associated with cleaning needles/syringes for reuse (aOR:1.5, 1.1–2.1)

Darke et al. [39]

Australia

Participants who had borrowed used injecting equipment in the preceding month had significantly more current health-related problems at their injecting sites than other participants (3.1 vs. 2.1, t = 3.7, P < 0.001)

Hope et al. [38]

England

Higher levels of reported symptoms of infections were associated with sharing filters in the last four weeks (aOR: 1.31, 0.9–1.59). No strong evidence was found for sharing spoons

Rance et al. [40]

Australia

75% of participants reported sharing within their partnership. Only one participant reported sharing with someone other than their partner, while eight couples reported never sharing.

Of the 26 couples who reported sharing needle–syringes, 20 believed they were hepatitis C virus (HCV) concordant (8 HCV negative and 12 HCV positive) and 14 discordant (8 HCV-positive men and 6 HCV-positive women)

Murphy et al. [31]

USA

Use of a needle after someone else had used it (p = 0.005) and use of a dirty needle (p < 0.001) were both significantly more common among cases who reported a skin and soft tissue abscess than among controls

Wright et al. [41]

England

Participants reported sharing injecting equipment, in particular spoons and filters.

Re‐using cleaned needles despite being aware that cleaning may not be effective in reducing the risk of hepatitis C transmission was also identified

5. Rotating sites

Hope et al. [42]

Bristol

More than half of those surveyed reported having had a ‘missed hit’, and for a quarter this happened at least once a month, with around one in six reporting having a ‘missed hit’ more than four times a month.

Those who reported that they had experienced a ‘missed hit’ were twice as likely to also report having had symptoms of injection site infections and injuries

Harris and Rhodes [13]

England

The facilitation of venous access and care was an initial and enduring rationale for safe injecting practices. Difficult venous access resulted in increased contamination of injecting environments and transitions to femoral injecting.

Advice and information on how to avoid venous sclerosis, and how to find and safely access less visible veins, was desired by the majority

Structural constraints act as barrier to safer injecting practices and contribute to greater risk of developing bacterial skin infections among people who inject drugs

Access to handwashing facilities among homeless people who inject drugs

Harris et al. [36]

England

Funding cuts have impacted not only on housing and welfare provision but access to clean water on the city streets among unstably housed people who inject drugs

Wright et al. [41]

England

Participants reported injecting in a variety of outdoor public places, while they were homeless, including derelict buildings, back alleys, bushes and underneath bridges

Citric acid sachet size

Harris et al. [35]

England

Acid sachet size poses a constraint to good practice. The sachet size is a strong signifier of appropriate quantity

Access to sterile water for injection preparation

Harris et al. [36]

England

Funding cuts have impacted not only on housing and welfare provision but access to clean water on the city streets (e.g. closure of public toilet and increased security in pubs and cafes) among unstably housed people who inject drugs.

Drug treatment services, facing sustained budgets cuts of at least 18%, have reduced costs where possible, impacting on the availability of water provision in needle and syringe programme equipment packs

Access to sterile equipment

McNeil and Small [45]

International

Needle and syringe programmes increase access to material resources and safer injecting education. This is a facilitating factor.

Participants expressed understanding that safer environment interventions reduced an array of risks by changing physical and social environments (Kerr et al. 43; Small et al. 44)

Injecting environment

Dunleavy et al. [11]

Scotland

Participants reported injecting in indoor environments that were unhygienic and higher risk practice when injecting new psychoactive substances.

Participants’ experience of skin and soft tissue infections could cause panic and stigma; there was limited knowledge of skin and soft tissue infections prior to first-hand experience

Wright et al. [41]

England

Participants reported injecting in a variety of outdoor public places, while they were homeless, including derelict buildings, back alleys, bushes and underneath bridges. Participants also reported urgency of injecting outside