29 November 2023


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Dead space in syringes have been discussed in the harm reduction context since the 1990s, and many researchers and activists have argued their benefits. This report explores the support for low dead space syringes and needles (LDSS/N) in line with WHO guidelines for HIV and HCV prevention. It emphasizes the importance of considering factors such as client preferences and incorporating LDSS/N into a comprehensive harm reduction package.


Harm reduction services for people who inject drugs are essential interventions. They offer non-judgmental services to a criminalised and stigmatised community and are key public health measures to prevent and control infectious diseases such as HIV and hepatitis C virus (HCV).

Injecting drug use is documented in 190 of 207 countries and territories and it is estimated that globally there are 14.8 million people (aged 15-64 years) who inject drugs. The World Health Organization (WHO) and other international organisations have recommended access to comprehensive harm reduction services to prevent the spread of blood borne diseases for more than a decade. Despite this, harm reduction services are under-resourced and not implemented at scale. Although systematic literature reviews found that high coverage NSP can be effective in reducing HIV and HCV infection risks; only five countries around the globe are providing high coverage of both needle and syringe programmes (NSPs) and opioid agonist treatment (OAT).

There are many tools for HIV and HCV prevention amongst people who use drugs, though access, availability, and acceptability remains a challenge in many countries. Low dead space syringes and needles (LDSS) is one such tool. Direct sharing of needles and syringes account for most HIV and HCV infections among people who inject drugs in many countries. A recent modelling study estimated that removing the transmission risk due to injecting drug use could prevent 43% of all new HCV infections globally. As a result, the design of needles and syringes distributed in harm reduction programmes should be a consideration in efforts to reduce infections.

All needle and syringe combinations have dead space (see box on syringe dead space), because some void area remains even when the plunger of the syringe is fully depressed. When people who inject drugs share their injecting equipment, the volume of dead space is an important determinant of the volume of blood that is transferred from one person to another. The less residual fluid that remains in a syringe and needle combination, the less blood is transferred if or when the equipment is shared. Studies on syringe dead space suggest that regular syringes with detachable needles can contain ten times more dead space compared to syringes with fixed needles.

Dead space in syringes have been discussed in the harm reduction context since the 1990s, and many researchers and activists have argued that the potential benefits of LDSS compared to high dead space syringes and needles (HDSS) are sufficient to support an overall switch to LDSS at NSPs. It is hypothesised that LDSS can reduce HIV and HCV transmission risk, as experiments showed that the volume of the residual fluid (blood) in the syringe following injection, is a key factor in the survival of these viruses in syringes; both HIV and HCV can survive longer in higher volumes of blood. Epidemiological studies found HDSS use to be associated with higher HIV prevalence rates, while exclusive LDSS use was associated with reduced HCV incidence, though more evidence is still needed in this regard.

Modelling shows that LDSS use could result in a decrease both for HIV and HCV prevalence. Furthermore, the results of a recent threshold analyses indicated that compared to HDSS, detachable LDSS would only need to reduce the risk of virus transmission by 0.26% to be cost saving and 0.04% to be cost-effective in a high-income setting. Although sufficient coverage of NSP should be prioritised at all times, there is an argument to be made that switching people who inject drugs from HDSS to LDSS should be included in comprehensive blood borne virus prevention programmes, as it could increase the effectiveness of NSPs even when coverage is inadequate. Reflecting the mounting evidence in the literature, the inclusion of LDSS at NSPs has been included in WHO guidelines and recommendations on HIV and HCV prevention since 2012. Recent updates of similar guidelines, for example, the UK’s National Institute for Health and Care Excellence (NICE) NSP guidelines, and the European Centre for Disease Prevention and Control (ECDC) and the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) joint guidance on the prevention of infectious diseases among people who inject drugs added explicit references to LDSS as equipment that should be offered at NSPs, together with information on its benefits.

However, different types of syringes and needles are needed for injecting, and large volume syringes with detachable needles are often central in drug injecting practices. For example, larger needle sizes and lengths are needed to access deeper femoral veins or intramuscular injection. Furthermore, injecting homemade drug mixtures, viscous liquids or pharmaceuticals and large volume drug solutions in general require larger volume syringes. Detachable needles can have practical benefits too, they can be replaced if they become blunt or clogged without losing the drugs already in the syringe. Additionally, the use of HDSS can reflect culturally mediated behaviours, for example, peer initiation and early experiences of injecting can influence injecting practices and equipment choice, and equipment can become an important part of injecting rituals. People who inject drugs can be reluctant to switch their usual injecting equipment because routines can help to inject successfully or overcome difficulties like finding a vein or injecting while in withdrawal.


To map syringe types at NSPs around the globe, a survey was developed with thematic sections focusing on syringe and needle distribution, and number of clients visiting NSPs – with detailed questions on the type of syringes and needles that are available at the programme (including brand name, volume of the syringe, needle gauge). Estimates on syringe access outside of harm reduction services (for example at pharmacies) were requested. Additionally, the questionnaire included open ended questions on procurement of needles and syringes and service providers’ experiences about syringe preferences among their clients. A literature review on LDSS was also conducted. Survey data collection was complemented by expert interviews with key stakeholders from Australia, Greece, Kyrgyzstan, Nigeria, Puerto Rico, Scotland, and Tanzania. The interviews were supplemented with data collection, which provided a clear understanding of NSP delivery structures, focusing on funding, syringe procurement and client preferences.

To ensure geographic and income diversity (mix of low-, middle-, and high-income countries), countries included in the survey were selected with random sampling based on the countries where needle and syringe programmes are available according to the Global State of Harm Reduction 2022 report. The number of people who inject drugs in a country, along with HIV and HCV prevalence among people who inject drugs, was considered; all countries included in UNITAID’s hepatitis C project (Armenia, Egypt, Georgia, India, Kyrgyzstan, Nigeria, South Africa, Tanzania, Ukraine, Vietnam) were included.

NSP service providers were mapped in the selected countries and invited to complete the survey questionnaire. Where country level data collection exists on NSP provision (either collected by government or organisations responsible for NSP implementation), data access was requested. In the case of Australia and Switzerland (where country level data on NSPs is collected), representatives in every canton/state/territory were approached and asked to provide data or expert estimates on the proportion of LDSS among the distributed needles and syringes.

The survey questionnaire was aimed at service providers. It requested data on the type of needles and syringes provided and the numbers of needles and syringes distributed, as well as their insights on client preferences regarding syringe types. A Russian translation of the questionnaire was used in Russia and Kyrgyzstan. The survey was translated into Spanish for Colombian respondents.



Funding for NSPs comes from both international and national resources. International funding is the primary, and often the only, source of funding for harm reduction in the low- and middle-income countries in our sample. Programmes that are domestically funded are found in high income countries. International funding is almost exclusively provided by the Global Fund to Fight AIDS, Tuberculosis and Malaria (the Global Fund). In Nigeria, South Africa and Thailand, the U.S. President’s Emergency Plan for AIDS Relief (PEPFAR) was among the major donors. The Alliance for Public Health (an organisation responsible for harm reduction initiatives in Ukraine) was funded by other donors as well as the Global Fund.

Syringe procurement is somewhat centralised in most countries. In countries where the Global Fund is the main source of funding, the Principal Recipient purchases all harm reduction equipment and distributes it to the organisations implementing harm reduction programmes. This process can lead to different results in terms of the type of available syringes. For example, in Kyrgyzstan, all syringes are purchased centrally but only HDSS are purchased because they are cheaper than LDSS. As a result, LDSS are not available in the country’s NSPs, but a diverse set of syringes from 1ml to 10ml are available. In South Africa, the Principal Recipient only purchases 1ml insulin type syringes with fixed needles, the most common LDSS. So, in South Africa there is only one type of syringe available, but all syringes are LDSS. In Armenia, NSPs are funded by the Global Fund through a local institution (National Centre for Infectious Diseases) purchasing harm reduction equipment, and there is a set limit on the available number of syringes for NSP clients per year (200). However, this does not cover the needs of local people who inject drugs, and NSPs are unable to provide an adequate number of syringes and needles. Another issue with international funding for NSPs is sustainability when domestic funding is not guaranteed; for example, in Albania, the Global Fund will end its support for harm reduction in 2024, putting service providers in a precarious situation.

In countries where national or local governments fund harm reduction services, NSPs can obtain their equipment according to public procurement policies. A typical, more centralised mode of procurement is when one or more medical equipment supplier is chosen by the government, service providers order the equipment they need, and the government matches the expenses. This is the case, for example, in some states/territories in Australia and Scotland. An example of a more decentralized version is Switzerland, where in some cantons, service providers are able to purchase the equipment they need autonomously. The canton pays for their orders trusting the service providers to choose the best value for money. In other countries, public procurement policies can hinder access to the best equipment available. In North Macedonia (where LDSS are not available at NSPs), service providers can only order their equipment through a public procurement system and must choose the cheapest option even if it is not the best quality equipment.


NSPs in low- and middle-income countries are currently less likely to distribute LDSS to people who inject drugs, while NSPs in high income countries are more likely to distribute a diverse range of needles and syringes including LDSS. The proportion of LDSS among the distributed syringes is 25% or less in most of the participating countries (17 out of 26 countries) and LDSS are not available at NSPs in nine countries. Traditional HDSS syringes with detachable needles were the most common type of syringes, they were available in all countries except three (Colombia, Puerto Rico and South Africa). New LDSS versions of large barrels and detachable needles were available only in Scotland. Central procurement systems are central in determining the type of syringes available at NSPs, and sometimes budgetary limitations influence decisions on harm reduction equipment procurement more than long-term public health goals.

All procurement and equipment decisions should be made with people who use drugs and harm reduction professionals. Generally, preferences on needle and syringe types are based on practical considerations like the volume of the solution or the site of injection, though habits and past experiences are also important. The latter is especially important when new equipment is introduced. Concerns in the community should be addressed before new style detachable LDSS are introduced, and the availability of new LDSS should be accompanied by dissemination of information on advantages of the approach (for example, reduced transmission of communicable diseases, less waste of drugs).

Although the issue of increased risk of transmission due to residual fluid in HDSS emerged decades ago, routine data collections generally do not include information on the type of syringes distributed in harm reduction programmes. It would be strategic to incorporate syringe types as part of data collection, not only because it has the potential to impact the public health outcomes of NSPs, but because the quality and the variety of equipment is important for people who use drugs. In many countries around the world, people who inject drugs can obtain injecting equipment only from harm reduction programmes. As the main source of sterile injecting equipment, it is important to offer good quality needles and syringes in appropriate variety covering the needs of the local community.

The availability of LDSS and needles is only one measure in a complex array of harm reduction services that should be available for every person who injects drugs. LDSS should be considered one part of a comprehensive harm reduction intervention, implemented to reach underserved populations like people living in remote, rural areas, women who use drugs, Indigenous, ethnic minority and other subpopulations of people who inject drugs in the intersections of multiple vulnerabilities. Although reaching high coverage of harm reduction interventions should be prioritised, it is strategic to also increase the impact of existing programmes. LDSS provision can be an important addition to implement NSP, opioid agonist therapy and naloxone distribution with appropriate coverage of services and unrestricted provision of injecting equipment.

The available evidence suggests that LDSS could be a cost-effective tool to decrease HIV and HCV prevalence among people who inject drugs, thus introducing LDSS or increasing their distribution at NSPs could be a way to improve already established services. However, consulting the local community is vital to ensuring that provided equipment is suitable, and accompanied with messages that are appropriate to support the uptake of LDSS.


This report was written by Robert Csák. This report was made possible by the collaborative input of: Annie Madden, INPUD; Peter Vickerman and Jack Stone, University of Bristol; Ernst Wisse and Pauline Lamand, Médecins du Monde.

Thanks are also owed to the following Harm Reduction International staff for feedback and support in preparing this report: Colleen Daniels, Naomi Burke-Shyne, Ajeng Larasati, Marcela Jofre, Cinzia Brentari, Giada Girelli, Suchitra Rajagopalan, Lucy O’Hare, Maddie O’Hare, Temitope Salami, and Anne Taiwo.

This report was made possible by a financial contribution from Unitaid. Project partners include: Médecins du Monde, International Network of People who Use Drugs (INPUD), Burnet Institute and University of Bristol. Its contents are the sole responsibility of Harm Reduction International.

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