Unsafe injections in the developing world and transmission of bloodborne pathogens: a review

Literature review which summarises studies that assessed injection safety and injection frequency, as well as studies estimating the strength of the association between unsafe injections and infections with bloodborne pathogens. Document in pdf format; Acrobat Reader required.

Transmission of hepatitis B, hepatitis C and human immunodeficiency viruses through unsafe injections in the developing world: model-based regional estimates

This mathematical model provides an estimate of the incidence of injection-associated infections with hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV). Document in pdf format; Acrobat Reader required.

Unsafe injections in the developing world and transmission of bloodborne pathogens: a review.

Unsafe injections are suspected to occur routinely in developing countries. We carried out a literature review to quantify the prevalence of unsafe injections and to assess the disease burden of bloodborne infections attributable to this practice. Quantitative information on injection use and unsafe injections (defined as the reuse of syringe or needle between patients without sterilization) was obtained by reviewing the published literature and unpublished WHO reports. The transmissibility of hepatitis B and C viruses and human immunodeficiency virus (HIV) was estimated using data from studies of needle-stick injuries. Finally, all epidemiological studies that linked unsafe injections and bloodborne infections were evaluated to assess the attributable burden of bloodborne infections. It was estimated that each person in the developing world receives 1.5 injections per year on average. However, institutionalized children, and children and adults who are ill or hospitalized, including those infected with HIV, are often exposed to 10-100 times as many injections. An average of 95% of all injections are therapeutic, the majority of which were judged to be unnecessary. At least 50% of injections were unsafe in 14 of 19 countries (representing five developing world regions) for which data were available. Eighteen studies reported a convincing link between unsafe injections and the transmission of hepatitis B and C, HIV, Ebola and Lassa virus infections and malaria. Five studies attributed 20-80% of all new hepatitis B infections to unsafe injections, while three implicated unsafe injections as a major mode of transmission of hepatitis C. In conclusion, unsafe injections occur routinely in most developing world regions, implying a significant potential for the transmission of any bloodborne pathogen. Unsafe injections currently account for a significant proportion of all new hepatitis B and C infections. This situation needs to be addressed immediately, as a political and policy issue, with responsibilities clearly defined at the global, country and community levels.

PIP: Unsafe injections and the consequent transmission of bloodborne pathogens are suspected to occur routinely in the developing world. This paper presents a review of the literature to determine the prevalence of unsafe injection practices and assess the disease burden of bloodborne infections. Quantitative data on injection usage and unsafe injection practices, such as the reuse of unsterilized syringe or needles between patients, is obtained by reviewing published articles and unpublished reports of the WHO. In addition, the transmissibility of hepatitis B and C viruses and HIV was determined using information from studies of needle-stick injuries. All epidemiological researches that associate injections with bloodborne diseases were examined to assess the attributable burden of bloodborne infections. It was estimated that each person in developing countries receives an average of 1.5 injections per annum. However, institutionalized children, children and adults who are sick or confined in hospitals, often receive 10-100 times as many injections. Of these injections, 95% are therapeutic, a majority of which are unnecessary. At least 50% of injections in 14 of 19 countries were unsafe. Furthermore, 18 studies present convincing evidence on the association of unsafe injection practices and the transmission of bloodborne viruses such as hepatitis B and C, Ebola, Lassa virus infections and malaria. Such practices account for a significant number of hepatitis B and C infections.

Transmission of hepatitis B, hepatitis C and human immunodeficiency viruses through unsafe injections in the developing world: model-based regional estimates.

Thousands of millions of injections are delivered every year in developing countries, many of them unsafe, and the transmission of certain bloodborne pathogens via this route is thought to be a major public health problem. In this article we report global and regional estimates of the number of hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections that may occur from unsafe injections in the developing world. The estimates were determined using quantitative data on unsafe injection practices, transmission efficiency and disease burden of HBV, HCV and HIV and the prevalence of injection use obtained from a review of the literature. A simple mass-action model was used consisting of a generalized linear equation with variables accounting for the prevalence of a pathogen in a population, susceptibility of a population, transmission efficiency of the pathogen, proportion of injections that are unsafe, and the number of injections received. The model was applied to world census data to generate conservative estimates of incidence of transmission of bloodborne pathogens that may be attributable to unsafe injections. The model suggests that approximately 8-16 million HBV, 2.3-4.7 million HCV and 80,000-160,000 HIV infections may result every year from unsafe injections. The estimated range for HBV infections is in accordance with several epidemiological studies that attributed at least 20% of all new HBV infections to unsafe injections in developing countries. Our results suggest that unsafe injections may lead to a high number of infections with bloodborne pathogens. A major initiative is therefore needed to improve injection safety and decrease injection overuse in many countries.

PIP: This paper reports global and regional estimates of the prevalence of hepatitis B virus (HBV), hepatitis C virus (HBV), and HIV infections that may occur as a result of unsafe injection practices in the developing countries. The estimates were determined using quantitative information on unsafe injection practices, transmission efficiency of pathogen, and disease burden of hepatitis B and C viruses, as well as HIV and the prevalence of injection usage as observed in the literature reviews. A simple mass-action model was utilized in the study and was applied to world census data to generate the conservative estimates of interest. The model showed that about 8-16 million HBV, 2.3-4.7 million HCV, and 80,000-160,000 HIV infections may result from unsafe injections each year. It was also noted that the estimated range of HBV infection is consistent with a number of epidemiological studies that attribute at least 20% of all new cases of HBV infection to unsafe injections in the developing world. Given that unsafe injections may contribute to a high number of infections with bloodborne pathogens, a major effort is necessitated to improve injection safety and reduce injection overuse in many countries.

Vaccine transport and storage: environmental challenges.

This paper describes the current status of the vaccine cold chain that was developed in the 1970s. It then describes the changes that are likely to take place in the next 5 to 10 years and their potential impact on the existing system. For more than 20 years, the cold chain system and vaccine handling rules have been set to the speed of the most fragile of the EPI vaccines namely: Oral Polio Vaccine. This has led to the establishment by WHO of stringent vaccine handling rules and Standard Performance Specifications for cold chain equipment. Major changes are occurring that will impact on immunization programmes: The introduction of Vaccine Vial Monitor (VVM), the prospect of an increase in the stability of OPV and the worldwide ban on refrigeration gases and insulation foaming agents.

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

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 equipment that is used, technology alone cannot totally eliminate the risk. A knowledge of the cost, practicality 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 practices. 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.

PIP: Every year, more than 550 million injections are administered in developing countries through the Expanded Program on Immunization. It is imperative that great care be given to providing these immunizations with only sterile injection equipment. Otherwise, children may be subjected during immunization to infections such as hepatitis B virus and HIV. Sterilizable needles and syringes, standard disposable needles and syringes, autodestruct needles and syringes, and jet injectors are currently available for administering vaccines. The design and operation of the former two types of needles and syringes are, by definition, evident. The design of autodestruct needles and syringes and jet injectors, however, is less directly apparent from their nomenclature. Autodestruct syringes have a device in the barrel which prevents the plunger from being redrawn after a single use, thereby automatically blocking the syringe and preventing it from being reused. Jet injectors deliver immunizations with a high pressure jet of fluid generated by either a hydraulic or mechanical compression system. This equipment was developed for high workload use and has been employed in immunization campaigns for many years. Low workload injectors are being developed for use in the small immunization clinic setting. In general, the cost per injection is lowest with sterilizable equipment and highest with the autodestruct device. Only autodestruct syringes, however, virtually eliminate the risk of unsafe injection practices. It must be emphasized that technology alone cannot eliminate the risk of accidental infection using unsterile injection equipment. The authors note that it may be appropriate in some settings 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.