Reducing the risk of unsafe injections in immunization programmes: financial and operational implications of various injection technologies.

Reviews/Analyses Reducing the risk of unsafe injections in immunization programmes: financial and operational implications of various injection technologies* B. Aylward,1 J. Lloyd,2 M. Zaffran,2 R. McNair-Scott,3 & P. Evans2 The unsafe use and disposal of injection equipment continues to put patients, health care workers, and the general community at risk of infections such as hepatitis B virus and human immunodeficiency virus. Although the potential for unsafe injection practices varies substantially with the type of equip- ment that is used, technology alone cannot totally eliminate the risk. A knowledge of the cost, practical- ity and, most importantly, the potential for misuse, is critical for selecting the most appropriate injection equipment for each immunization setting. Four types of injection equipment are currently available for administering vaccines: sterilizable needles and syringes; standard disposable needles and syringes; autodestruct needles and syringes; and jet injectors. In general, the cost per injection is lowest with sterilizable equipment and highest with autodestruct. However, only autodestruct syringes virtually eliminate the risk of unsafe injection prac- tices. Owing to differences in cost and programme factors, in some settings it may be appropriate to use a combination of equipment. For example, autodestruct syringes may be used in areas where it is difficult to ensure adequate supervision, while in medium-sized, fixed-site clinics with safe injection practices, sterilizable equipment will be the most cost-effective. Introduction Unsterile medical practices continue to contribute to the transmission of pathogens such as human immu- nodeficiency virus (HIV) and hepatitis virus B, des- pite advances in injection equipment and a better understanding of the risks of cross-infections (1-4). Although reports from industrialized countries have dominated the published literature on such out- breaks, the problem is potentially much greater in developing countries, where the prevalence of both injections and bloodbome pathogens is substantially higher (5-7). * From: Global Programme for Vaccines and Immunization, World Health Organization, 1211 Geneva 27, Switzerland. I Medical Officer. 2 Technical Officer. Requests for reprints should be sent to Mr J. Lloyd. 3 Formerly, Medical Officer. Reprint No. 5630 Every year over 550 million injections are administered in developing countries through the Expanded Programme on Immunization (EPI) alone.a Even if these injections comprise only a fraction of the skin-piercing procedures that are performed, safety must be a leading concern. The HIV epidemic has highlighted the need to ensure that individuals are only exposed to those invasive procedures that are necessary and safe (8). Although immunizations are necessary, public awareness of the consequences of unsterile practices has already threatened to reduce their acceptability (9). Incorrect immunization practices, which could result in outbreaks of bloodbome diseases, continue to occur (10, 11) despite EPI's longstanding policy that "a single sterile needle and a single sterile syringe should be used with each injection" (12). To perform safe immunizations, health care workers a EPI. Information system report 1993. Unpublished document WHO/EPI/CEIS/93.1, 1993. Bulletin of the World Health Organization, 1995, 73 (4): 531-540 © World Health Organization 1995 531 B. Aylward et al. require a knowledge of sterilization, immunization and disposal procedures, the motivation and supervi- sion to perform properly these procedures, and an adequate supply of appropriate injection equipment. EPI has previously developed a wide range of materials on the training and supervision of health care workers.b This review article briefly deals with the complications of unsafe injections, examines the potential risk of transmitting bloodbome organisms with the available injection equipment, and discusses the financial and operational implications of using each type of equipment. The overall aim is to present the strategies needed to reduce the risk of unsafe injections in immunization programmes. Risks associated with unsafe injection practices Immunization injections are only safe when the cor- rect vaccine is properly administered with sterile equipment that is disposed of safely.c Unsafe injec- tions can result in infectious and noninfectious com- plications (Fig. 1). The infectious complications can be divided into the following categories: transmis- sion of bloodbome pathogens; and other iatrogenic infections. The noninfectious complications can be divided into injuries from improper injection tech- niques and reactions to incorrect injection sub- stances. Based on the frequency of published reports, infectious complications probably account for the majority of injection-associated illnesses (13). The risk of transmitting a bloodbome disease depends on the local injection practices, the number of injections an individual receives, and the prevalence and trans- missibility of the bloodbome organisms (14, 15). The risk of contracting an infectious disease from unsafe injection practices is not limited to the person who receives the injection; bloodbome dis- eases can be transmitted from patient to patient, patient to health care worker (HCW), and patient to the general community (16). Patient-to-patient trans- mission results primarily from injections with con- taminated equipment. Patient-to-HCW cross-infec- tion is usually due to accidental needlesticks while cleaning contaminated sterilizable needles, recapping used disposable needles, or improperly disposing of either (a study in Pakistan found that immunization workers suffered needlestick injuries at a rate of 1 per 500 injections (17)). Patient-to-community trans- b Immunization in practice - syringes, needles, and steriliza- tion. Unpublished WHO document EPI/PHW/84/2 (Rev.1), 1987. c Safety of injections in immunization services: WHO recom- mended policy. Unpublished document WHO/EPI/LHIS/94.1, 1994. Fig. 1. Categorization of complications associated with unsafe injection practices. Potential complications Infectious Non-infectious Transmission of latrogenic infections Injuries due Incorrect bloodbome due to unsterile to improper injection pathogens equipment technique materials Examples Examples Examples Examples Hepatitis B Abscesses Traumatic paralysis Toxic injection HIV Septicaemia BCG lymphadenitis Anaphylactic shock Dengue Tetanus Malaria mWo95156 mission can occur when used injection equipment is not properly disposed of by burning (destructive incineration) or burying. Members of the general community may also be exposed to bloodborne pathogens through accidental needlestick injuries or reuse of contaminated equipment within or outside the formal medical sector. A high prevalence of unsafe injections and infectious complications has been documented glo- bally, particularly in developing countries (13). One study in West Africa estimated that the annual inci- dence of iatrogenic gluteal abscess in the local com- munity was 231 per 100 000 population (6). Also, in an East African country, 134 out of 360 households covered in an injection practices survey reported that at least one family member had developed an abscess following a recent medical injection.d Reducing the risk of injection- associated infections Minimizing the risk of injection-associated infec- tions requires a comprehensive strategy, an impor- tant component of which is the selection and supply of appropriate equipment (Table 1). EPI recom- mends a range of injection and sterilization equip- ment and has outlined the critical steps for their safe use.e Although incorrect use of any of the available equipment can result in the transmission of blood- borne organisms, the potential for misuse varies significantly with the type of equipment. d Birungi H et al. Injection use and practices in Busoga, east- ern Uganda. Unpublished WHO document, 1994. e See footnote c. 532 WHO Bulletin OMS. Vol 73 1995 Reducing the risk of unsafe immunization injections Table 1: Components of an Immunization safe-injection strategy Components Principal activities Baseline assessment Evaluate injection policies and practices Make an inventory of the existing injection, sterilization, and disposal equipment Identify the obstacles to safe injections Selection of injection, sterilization, and disposal equipment Choose equipment that minimizes the risk of misuse in each immu- nization setting Calculate the equipment needed to reach coverage targets and maintain a reserve stock Ensure proper facilities for sterilization and/or disposal of used equipment Budget and supply of the required equipment Estimate the capital and recurrent costs of injection, sterilization, and disposal Develop an adequate budget for both capital and recurrent costs Ensure a supply and financing mechanism for adequate quantities of injection equipment Public education Generate an awareness of injection risks Create a demand for safe injections Promote the refusal of unsafe injections Health worker training Teach the risks of unsafe injections Provide training in proper use of injection, sterilization, and disposal equipment Clinic supervision Review and correct injection, sterilization, and disposal practices Ensure adequate reserve stocks of injection and sterilization equip- ment Monitoring of adverse events after immunization Determine whether complications are due to unsafe injection practices and take appropriate action Because of inadequate supervision, unsafe immunization injections have continued to occur in settings where health workers have been properly trained (18, 19). This had led to suggestions that the only way to ensure safe injections is to use equip- ment that has no potential for misuse (20). EPI has continuously supported the development of equip- ment that reduces the possibility of unsafe practices,' but the use of technology to eliminate the risk to patients, HCWs and the general community can be both operationally difficult and expensive. Therefore, it is critical that the reasons for noncompliance with safe practices are understood to ensure that the most appropriate equipment is selected for each immu- nization setting. The selection and supply of appropriate injection equipment can be as critical to the overall safety of f Expanded Programme on Immunization: report of the 1991 Technet consultation of experts in logistics for health to discuss technical developments in the EPI and establish plans of action on priority issues, Casablanca, Morocco, 10-22 November 1991. Unpublished document WHO/EPI/LHIS/92.1. an imunization programme as the existence of a clear policy, proper training, and effective supervision. Choosing the appropriate equipment should include consideration of its potential for unsafe injection practices, as well as factors such as cost, acceptabil- ity, and supply. Immunization injection equipment It is convenient to divide immunization injection equipment into the following categories: sterilizable needles and syringes; disposable needles and syringes; autodestruct syringes; and jet injectors. The equipment requirements and unit costs for each tech- nology are summarized in Table 2.9 Sterilizable equipment consists of a glass or plastic syringe with a stainless steel needle, both of which must be steam-sterilized for 20 minutes at 121-126 °C prior to use. Immediately after an injec- 9 UNICEF. Copenhagen warehouse catalogue price list, Janu- ary-June 1994. Copenhagen, 1993. WHO Bulletin OMS. Vol 73 1995 533 B. Aylward et al. Table 2: Equipment requirements and unit costs for four injection technologies used to administer Injectable vaccines Injection Unit Costa equipment Equipment required (US$) Sterilizable Plastic BCG syringe 0.23 Plastic 0.5-ml syringe (DPT, TT, measles)b 0.18 Hypodermic needle (22-gauge) 0.038 Steam sterilizer (double-rack) 75.26 Disposablec BCG disposable syringe with needle 0.06 Plastic 2-ml syringe 0.02 Hypodermic needle (22-gauge) 0.017 Incinerator disposal box (100 syringes) 0.85 Autodestruct Autodestruct syringe with needle 0.08 (includes 1 incinerator box per 100 syringes) Jet injectorc Jet injector (high workload) 2 991.13 Spare parts for jet injector 772.76 Steam sterilizer 65.48 a 1994 UNICEF catalogue costs. Low workload jet injectors are not yet available through UNICEF. b DPT = diphtheria-pertussis-tetanus; TT = tetanus toxoid. c UNICEF does not provide disposable equipment for immunization programmes. Costs are provided for purposes of comparison. tion, the syringe and needle must be soaked, cleaned of visible debris, and steam-sterilized before reuse. The life span of a sterilizable needle and syringe is 50-200 injections, depending on the local water hardness. In some areas, the life span can be pro- longed by placing a hard water pad (US$ 10.00- 20.00) in the sterilizer. A "TST spot" (time, steam, and temperature indicator; US$ 0.07 per indicator) should be included with each sterilization load to en- sure that sterilization parameters have been met. Disposable needles and syringes are sterilized at the time of manufacture and then packaged with an expiry date after which their sterility cannot be guar- anteed. They are designed for single use and must then be disposed of safely. In general, only destruc- tion by burning at high temperatures (destructive incineration) can ensure that the needles and syringes are free of bloodborne pathogens and incapable of being reused. Autodestruct syringes were first commercially produced for use in EPI (21). Such syringes have a device in the barrel to prevent the plunger from being redrawn after a single use, thus automatically blocking the syringe and preventing it from being reused. At the time of manufacture, a needle is attached to each syringe and the unit is sterilized and packaged individually. The container in which auto- destruct syringes are supplied is a "bum box", which ensures that the equipment is destroyed relatively quickly. The autodestruct syringes currently used in EPI are calibrated for 0.5 ml, the standard dose for all EPI vaccines except BCG; an autodestruct syringe calibrated for BCG will be available in the near future. Jet injectors deliver immunizations with a high pressure jet of fluid generated by either a hydraulic or mechanical compression system. Such injectors were developed for high workload use and have been employed in immunization campaigns for many years (22, 23). With the development of low work- load injectors that can be loaded by hand and have a life span of at least 20 000 injections, this technology may soon be applicable to the small immunization clinic setting.h Potential risks of bloodborne infections Injection-associated infections can result from errors made during the preparation of the equipment (inclu- ding sterilization), the immunization, and/or the dis- posal of contaminated equipment. The potential risks of patient-to-patient, patient-to-HCW or patient-to- community transmission for each injection technol- ogy are summarized in Table 3 and explained below. Of the four technologies, the risk of unsafe prac- tices that could expose patients or HCWs to blood- h Jet guns on trial. Technet news - logistics for health, 1993, 93(2): 4. 534 WHO Bulletin OMS. Vol 73 1995 Reducing the risk of unsafe immunization injections Table 3: Comparison of the potential risks of transmitting bloodborne pathogens through specific unsafe injection practices with four types of injection equipment Transmission route:Injection equipment Patient-to-patient Patient-to-HCWa Patient-to-community Sterilizable High risk: equipment reused High risk: needlestick Low risk: needlesticks owing to without sterilization injuries when cleaning equipment unsafe disposal of needles Disposable High risk: equipment reuse Medium risk: injury during High risk: reuse within and instead of disposal reuse, recapping, or disposal outside of the medical sector Autodestruct No risk Low risk: needlesticks Low risk: needlestick injury during recapping or disposal owing to unsafe disposal Jet injector Low risk: continued use with No risk No risk contaminated injector nozzle a HCW = health care worker. borne pathogens is probably greatest with sterilizable syringes and needles. Proper cleaning and steriliza- tion of reusable needles and syringes requires eight separate steps; failure to conduct any step correctly could result in patient-to-patient disease transmis- sion, while the repeated handling of the equipment continually puts the HCW at risk. Since the needles and syringes are reused many times, the risk of trans- mitting disease to the community through unsafe dis- posal is lower than for single-use needles and syringes. Disposable syringes and needles present a risk of cross-infection because of their potential for reuse both within and outside immunization programmes. Shortage of injection materials is only one of the fac- tors that contribute to this phenomenon (13). In many cultures, particularly where resources are scarce, the disposal of syringes and needles after a single use appears needlessly wasteful (24). In such settings, the equipment may be reused, exposing both patients and HCWs to contaminated syringes and needles. The greatest risk may be to the general community, since inadequate disposal often leads to needlestick injuries and reuse of contaminated equipment outside the formal medical sector. UNICEF therefore no longer supplies standard dispos- able needles and syringes for use in immuniza- tion programmes.i The autodestruct syringe with a fixed needle is the only type that virtually eliminates the risk of patient-to-patient transmission of bloodbome infec- tions through reuse. Once used, the syringe cannot be reloaded to provide another injection. Since the equipment cannot be reused and safe disposal boxes are included at the time of distribution, there should be minimal handling of used syringes, lowering the risk to HCWs. Unsafe disposal can put the commu- United Nations Children's Fund. UNICEF Executive Direc- tive. Unpublished document CF/EXD/1992/006, 1992. nity at risk of bloodbome pathogens through needle- stick injuries, but this risk may be lower than for other equipment because incinerator boxes are included in the purchase price. Ideally, safe disposal of used equipment, wheth- er sterilizable or single-use, requires incineration at a high enough temperature to melt the needles. EPI is currently evaluating low volume incinerators that can generate temperatures of 1200-1400 °C in urban or rural settings. Jet injectors eliminate the risk of patient-to- HCW transmission but can result in patient-to- patient cross-infection if the injector head is not rou- tinely changed or sterilized between patients. Since sterilization of injector heads between patients is not practical in the immunization clinic setting, it is cur- rently recommended that the heads be swabbed after each injection and sterilized at the end of each ses- sion if they are visibly contaminated with blood. Transmission of hepatitis B virus has been reported with one type of jet injector (25), and a number of laboratory studies have documented the potential to transmit bloodbome pathogens with contaminated injectors (26, 27). Although this risk has generally been estimated to be very low, a study in an area with a high prevalence of hepatitis B virus estimated a theoretical risk of transmission as high as 1 per 388 to 1 per 3367 injections under suboptimal conditions (28). The risk of cross-infection can be reduced several fold, however, by swabbing the nozzle with acetone or ethanol between injections. Because of differences in their mode of action, the risk of cross-infection with low workload jet injectors could theoretically be lower than that of high volume injectors. The low workload jet injec- tors that are being developed automatically clear the fluid pathway, minimizing the risk of contamination through backsplash. Prototype jet injectors that employ a single-use autodestruct sterilizable cap are being evaluated by EPI. These injectors have the WHO Bulletin OMS. Vol 73 1995 535 B. Aylward et al. potential to protect patients, HCWs, and the commu- nity, at a cost per injection between that of steriliz- able and autodestruct technology. However, such injectors are still under development and have to be appropriately field tested. Furthermore, the capital costs of making injectors with disposable caps avail- able to national EPI programmes on a global basis may prove prohibitive. Although safety considerations could be in- voked to support the universal use of autodestruct syringes in immunization programmes, this is not always operationally possible or necessary. A num- ber of factors will determine a programme's capacity to use a particular type of equipment. Because the cost of each type of injection device frequently has the greatest impact on the choice of technologies, this factor is considered in detail below. Costs of different injection strategies The overall cost of using a particular type of injec- tion equipment depends on its procurement costs, the local cost of fuel for sterilization and disposal, the life span of the item and the number of injections that are given during each immunization session. Table 4 compares the estimated total cost and cost per injection of using each of the four types of injection equipment in both a large (50 injections per day) and small (5 injections per day) clinic setting. The equipment costs shown in Table 2 were used and the following assumptions were made: immu- nization sessions were held 5 days per week; the usual life span of a steam sterilizer was 10 years; the cost of fuel for one sterilization session was US$ 0.25 (fixed cost for 1-84 syringes); and the dis- posal costs for burning used equipment in an inciner- ator box were US$ 0.85 for 100 syringes. Although these cost estimates are subject to wide variation, the examples illustrate several points about the cost of using each type of injection equip- ment. First, the size of the immunization session is an important determinant of the overall cost of using a particular device. In both settings, sterilizable equipment costs less than autodestruct; however, the financial advantage diminishes rapidly as the size of the immunization session decreases. Second, if fuel is expensive, the relative cost of autodestruct equip- ment falls markedly, particularly in the small clinic setting; if the price of fuel were double the amount used in Table 4, the cost per injection using autodes- truct and sterilizable equipment would be similar. Third, immunization programmes could adopt a mix of equipment (i.e., autodestruct for small sessions and sterilizable for larger clinics), without increasing the overall cost. Operational considerations Although cost often determines the type of injection equipment that is chosen for an immunization pro- gramme, other factors have a significant impact on how successfully a particular technology can be implemented. Among these factors are the acceptability of the equipment to the community and HCWs; the training and supervision required to ensure its cor- rect use; the feasibility of using the equipment in a particular setting; and the capacity to supply an adequate stock. Although it is commonly believed that commu- nities will refuse injections with sterilizable equip- ment, public reaction to its use is variable. A recent study in a country that is highly endemic for HIV found that immunization injections with reusable equipment were acceptable because the community Table 4: Estimated total costs and cost per injection of four injection technologies in a routine immunization programme over a 1-year period, by clinic workload Clinic workload of: 5 injections per day 50 injections per day Total Cost per Total Cost per Injection costs injection costs injection equipment (US$) (US$) (US$) (US$) Sterilizable 75.12 0.06 108.28 0.01 Disposable 69.55 0.05 695.50 0.05 Autodestruct 104.00 0.08 1040.00 0.08 Jet injector 121.55 0.09 380.00 0.03 (low workload)- a Low workload injectors will soon be available for use in immunization programmes. The manufacturer's price of US$ 250 per injector was used in the calculations. The addition of a sterile autodestruct cap would increase the cost by approximately US$ 0.02-0.03 per injection. WHO Bulletin OMS. Vol 73 1995536 Reducing the risk of unsafe Immunization injections was satisfied that the needles and syringes had been properly steam-sterilized.' The safe use of any injection equipment requires training and ongoing supervision. Supervision re- quirements are very different for each technology, with sterilizable and disposable equipment requiring greater attention than autodestruct. In areas where close supervision cannot be maintained, autodestruct equipment offers the advantage of guaranteed single use. The feasibility of using a particular technology depends on the immunization strategy employed. During routine immunization sessions, relatively small numbers of people are immunized through fixed sites, outreach clinics, and mobile teams. Steri- lizable equipment may be well suited to the fixed sites, but can be cumbersome to use in the other set- tings, even with sterilizer drums that can be trans- ported to the field without compromising the sterility of the syringes and needles.k In contrast, autodestruct syringes are readily portable and reduce the risk of unsafe injections in settings with minimal supervi- sion. During activities such as national immunization days (NIDs), large numbers of people, often more than 200, are immunized per session, either at fixed sites or through house-to-house visits. High work- load jet injectors are practical and cost-effective when used at fixed sites during NIDs, but require a large capital investment and cannot be taken from door to door. In contrast, autodestruct syringes can be used for either approach, without incurring the small potential risk of patient-to-patient disease transmission that exists with the high workload jet injector. Ensuring a consistent supply of injection materi- als, including sterilization equipment and spare parts, is a critical component of a safe injection strategy. The need to plan and budget for the procurement and distribution of sufficient injection equipment and reserve stocks is the most frequently overlooked aspect of safe injection plans. Because of the pos- sibility of an interruption in the supply of single-use needles and syringes, EPI recommends that steriliz- able needles and syringes always be available in set- tings where disposable or autodestruct technology is used. If sterilizable equipment is only used as a "backup", supervision is required to ensure that the required skills are not lost. J See footnote d, p. 532. kWHO/UNICEF. Technical series product information sheets 1993-94. Unpublished document WHO/UNICEF/EPI.TS/93.1, 1993. Ensuring the proper use of injection equipment Only when sterilizable, disposable, or autodestruct needles and syringes are properly used can they eli- minate the risk of exposing patients, HCWs, and the general community to infectious pathogens through immunization injections. Ensuring proper use of the equipment requires the thorough training of HCWs in safe injection practices, regular supervision of immunization sessions to achieve compliance with recommended practices, and the availability of a consistent and adequate supply of materials. Because changing an injection technology can require extensive investments in training and equip- ment, an assessment of the existing injection prac- tices should be conducted to evaluate whether a change in equipment is necessary. Such assessments should focus on the correct use of sterilizable equip- ment and the proper disposal of single-use needles and syringes. The flow chart in Fig. 2 shows how information from an assessment of injection could be used to improve the safety of an existing immunization programme. Following a baseline assessment, ongoing supervision of clinics and investigation of vaccine-associated adverse events should be used to monitor the safety of injection practices./ In countries where autodestruct equipment is warranted but which cannot afford its universal implementation, such equipment should be selective- ly targeted at areas where the risk of unsafe injec- tions is highest, e.g., where supervision is limited and/or immunization skills are not used on a daily basis. Since this is usually the case in small clinics, autodestruct syringes could markedly reduce the prevalence of unsafe injections, while minimally increasing the overall cost of a programme. Conclusions Current injection technology alone cannot totally eli- minate the potential for unsafe immunization prac- tices that could present a health risk for patients, HCWs, or the general community. Autodestruct equipment minimizes the risk to patients, while jet injectors virtually guarantee the safety of HCWs and the general community. The safety of immunizations can be maximized through the development of a national safe injection policy, effective HCW training and supervision, and adequate supply and I Surveillance of adverse events following immunization: field guide for managers of immunization programmes. Unpublished document WHO/EPI/TRAM/93.2, 1993. WHO Bulletin OMS. Vol 73 1995 537 B. Aylward et al. Fig. 2. Flow chart for ensuring the safe use of injection equipment. Assessment of immunization practices with existing injection technology Disposable Sterlizable Autodestruct needles and syringes equipment equipment Adequate supplies no Proper no Ensure safe disposal can be ensured? sterilization? of used equipment yes Use sterilizable yes Supervision can equipment alone be improved to or with autodestruct correct problem? II Continue with no sterilizable equipment Single use/safe disposal no can be guaranteed? Supervision can yes be improved to correct problem? Continue with e no disposable equipment Continue with autodestruct equipment Adequate resources to yes procure autodestruct equipment? no Adequate resources no Use mixed strategy to procure autodestruct - of sterlizable and equipment? autodestruct equipment + yes Use autodestruct equipment financing of the necessary equipment and means for its disposal. Advances in injection technology combined with effective supervision have allowed EPI to lower sub- stantially the risk of unsafe injections within nation- al immunization programmes. However, unsafe skin- piercing procedures performed by traditional healers, itinerant injectionists, and others continue to pose a major threat to the health of developing country pop- ulations (29). Although the first priority of EPI should be to guarantee the safety of its own injec- tions, it should also ensure that individuals are not exposed to infectious organisms through unsafe or unnecessary procedures performed outside the immunization setting. A major challenge for EPI will be to educate the public about the risks of all skin- piercing procedures, without compromising the acceptance of those interventions that are necessary and safe. Centers for Disease Prevention and Control, Atlanta, GA, USA; and United Nations Children's Fund, Copenhagen, for their technical advice and/or critical reviews of the manuscript. Resume Am6lioration de la s6curitX des injections dans les programmes de vaccination: incidences financibres et op6rationnelles de dift6rentes techniques d'injection Partout dans le monde, le non-respect des regles de sterilite lors des interventions medicales conti- nue de favoriser la transmission de pathogenes comme les virus de I'hepatite B et de I'immunod6- ficience humaine. L'utilisation et la destruction sans precautions du mat6riel d'injection exposent les patients, les agents de sante et 1'ensemble de la population au risque d'infections crois6es. Dans le cadre de sa strategie globale visant a assurer la securite des injections, le Programme elargi de Vaccination (PEV) encourage activement la re- cherche et le developpement, tant en ce qui con- WHO Bulletin OMS. Vol 73 1995 WHO 95159 Acknowledgements We thank staff in the WHO Regional Offices for the West- ern Pacific, Eastern Mediterranean, and South-East Asia; 538 Reducing the risk of unsafe immunization Injections cerne le materiel d'injection que sa sterilisation ou sa destruction. Si les risques lies aux pratiques d'injection dangereuses sont tres variables selon le type de materiel utilise, aucune technologie ne met totalement a l'abri des consequences d'une mauvaise utilisation. Pour bien choisir le materiel d'injection le plus approprie dans chaque cas, il est essentiel de tenir compte du cout et de la faci- lite d'emploi, mais surtout des risques de mauvai- se utilisation. 11 existe actuellement quatre types de mat6riel d'injection pour l'administration des vaccins: aiguilles et seringues st6rilisables, aiguilles et seringues a usage unique classiques; aiguilles et seringues autodestructibles; injecteurs a pression. En gen6ral, c'est avec le materiel st6rilisable que le coOt par injection est le plus faible et avec le materiel autodestructible qu'il est le plus eleve, mais ce dernier est le seul a eliminer pratique- ment les risques lies aux pratiques d'injection dangereuses. Etant donn6 les differences de coOt et de caract6ristiques operationnelles, il peut etre avantageux dans certains cas d'utiliser simultane- ment plusieurs types de materiel. Par exemple, des seringues autodestructibles pourraient etre utilisees dans les r6gions oO il est difficile d'exer- cer une surveillance adequate; par contre, si la securite des injections peut etre garantie, un materiel st6rilisable sera plus rentable dans des dispensaires fixes de taille moyenne. Les injec- teurs a pression seront reserv6s aux cas ou l'on doit pratiquer un grand nombre d'injections au cours d'une meme session, par exemple lors desjourn6es nationales de vaccination. 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