Unsafe Medical Injections Research Articles

Direct-Acting Antivirals Are Associated With Increased Risk of De novo Hepatocellular Carcinoma in HCV Cirrhotic Patients - Real World Data

Introduction: Chronic Hepatitis C virus (HCV) infection is common in Pakistan with estimated prevalence of 6.7% and a total of 10 million individuals infected with HCV and because of persistence of risk factors such as unsafe medical injections the prevalence continues to increase.. HCV treatment with Direct acting antivirals (DAAs) has been variably associated with an increased risk of HCC in cirrhotic patients. Two manuscripts showed increased risk but 3 larger studies have concluded that there is no increased risk. Methods: 662 HCV patients presenting in OPD of Doctors hospital & Medical center and Lahore General Hospital, Lahore were enrolled in this prospective observational study after confirming the eligibility criteria based on hematological, biochemical and virological studies. They were offered Pegylated IFN, sofosbuvir and ribavirin (12 weeks), sofosbuvir and ribavirin (24 weeks) or sofosbuvir, daclatasvir with or without ribavirin treatment (12-24 weeks) according to the national guidelines and preferences of the patient after an informed consent from October 2014 to March 2017. Patients were declared cirrhotic based on shear wave Elastography (Aixplorer) results.Occurrence of HCC was confirmed by a triphasic CT scan abdomen on MDCT 64 slice scanner. The primary outcome is the development of new HCC following SVR achieved with DAA. Results: Among 662,327 patients ( 49.4%) had evidence of cirrhosis. HCC was detected in 42(12.8%) patients suffering from cirrhosis with a mean age of 57.42 years (29-70), F/M ratio was 1.2:1. 22/42 were IFN naïve, 20/42 IFN exposed. Median time from exposure of DAAs to the development of HCC was 28 ± 10.2 weeks. None of the patients without cirrhosis developed HCC. HCC was detected in 29/256(11%) compensated cirrhotic and 13/71(18%) decompensated cirrhotic.20/42 had diabetes mellitus, 5/42 had BMI more than 35. 35/281(12.45%) developed HCC in patients who achieved SVR VS 5/40 (12.5%) in those who did not achieve SVR. SVR of two patients who developed HCC was not available. None of the baseline characteristics of the cohort including age, sex, obesity, Diabetes mellitus, genotype, previous interferon exposure, and advanced disease in form of decompensated cirrhosis was independent predictor for development of HCC Conclusion: It is concluded that despite effective eradication of HCV, HCC is more common in cirrhotic patients receiving direct acting antiviral therapy as compared to untreated cirrhotic patients as per historic control

A cross-sectional study of hepatitis C among people living with HIV in Cambodia: Prevalence, risk factors, and potential for targeted screening.

The epidemiology of hepatitis C in Cambodia is not well-known. We evaluated the prevalence of hepatitis C virus (HCV) and risk factors in the HIV cohort of Sihanouk Hospital Center of Hope in Phnom Penh to strengthen the evidence for suitable HCV testing strategies among people living with HIV (PLWH) in Cambodia. All consenting adult PLWH without a history of HCV treatment were tested for HCV between November 2014 and May 2016 according to the CDC algorithm (HCV antibody II electro-chemiluminescence immunoassay, followed by COBAS® AmpliPrep/COBAS® TaqMan® HCV PCR and INNO-LIA® HCV Score immunoblot end-testing). Genotyping was performed using the line probe assay Versant HCV genotype 2.0®. The study enrolled a total of 3045 patients (43% males, median age: 42.5 years, <1% high-risk). HCV antibodies were detected in 230 (7.6%; 95% confidence interval [CI] 6.6–8.5). Upon further testing, HCV antibodies were confirmed in 157 (5.2%; 95% CI 4.4–6.0) and active HCV in 106 (3.5%; 95% CI 2.8–4.2). Viremic prevalence peaked among men aged 50–55 years (7.3%) and women aged >55 years (11.2%). Genotype 1b (45%) and 6 (41%) were predominant. Coinfected patients had a higher aspartate-to-platelet ratio index, lower platelets, a lower HBsAg positivity rate and more frequent diabetes. Based on logistic regression, blood transfusion antecedents (adjusted odds ratio 2.9; 95% CI 1.7–4.9), unsafe medical injections (2.0; 1.3–3.2), and partner (3.4; 1.5–7.6) or household member (2.4; 1.3–3.2) with liver disease were independently associated with HCV in women. However, having a tattoo/scarification (1.9; 1.1–3.4) and household member (3.1; 1.3–7.3) with liver disease were associated with HCV in men. Thus, our study found intermediate endemicity of active hepatitis C in a large Cambodian HIV cohort and provides initial arguments for targeted HCV screening (>50 years, partner/household member with liver disease, diabetes, increased aspartate-to-platelet ratio index) as efficient way forward.

Evolution of the global burden of viral infections from unsafe medical injections, 2000-2010.

BackgroundIn 2000, the World Health Organization estimated that, in developing and transitional countries, unsafe injections accounted for respectively 5%, 32% and 40% of new infections with HIV, hepatitis B virus (HBV) and hepatitis C virus (HCV). Safe injection campaigns were organized worldwide. The present study sought to measure the progress in reducing the transmission of these viruses through unsafe injections over the subsequent decade.MethodsA mass action model was updated, to recalculate the number of injection-related HIV, HCV and HBV infections acquired in 2000 and provide estimates for 2010. Data about the annual number of unsafe injections were updated. HIV prevalence in various regions in 2000 and 2010 were calculated from UNAIDS data. The ratio of HIV prevalence in healthcare settings compared to the general population was estimated from a literature review. Improved regional estimates of the prevalence of HCV seropositivity, HBsAg and HBeAg antigenemia were used for 2000 and 2010. For HIV and HCV, revised estimates of the probability of transmission per episode of unsafe injection were used, with low and high values allowing sensitivity analyses.ResultsDespite a 13% population growth, there was a reduction of respectively 87% and 83% in the absolute numbers of HIV and HCV infections transmitted through injections. For HBV, the reduction was more marked (91%) due to the additional impact of vaccination. While injections-related cases had accounted for 4.6%–9.1% of newly acquired HIV infections in 2000, this proportion decreased to 0.7%–1.3% in 2010, when unsafe injections caused between 16,939 and 33,877 HIV infections, between 157,592 and 315,120 HCV infections, and 1,679,745 HBV infections.ConclusionFrom 2000 to 2010, substantial progress was made in reducing the burden of HIV, HCV and HBV infections transmitted through injections. In some regions, their elimination might become a reasonable public health goal.

Medical Injection Use Among Adults and Adolescents Aged 15 to 64 Years in Kenya

Unsafe medical injections remain a potential route of HIV transmission in Kenya. We used data from a national survey in Kenya to study the magnitude of medical injection use, medication preference, and disposal of medical waste in the community. The Kenya AIDS Indicator Survey 2012 was a nationally representative population-based survey. Among participants aged 15-64 years, data were collected regarding medical injections received in the year preceding the interview; blood samples were collected from participants for HIV testing. Of the 13,673 participants who answered questions on medical injections, 35.9% [95% confidence interval (CI): 34.5 to 37.3] reported receiving ≥1 injection in the past 12 months and 51.2% (95% CI: 49.7 to 52.8) preferred receiving an injection over a pill. Among those who received an injection from a health care provider, 95.9% (95% CI: 95.2 to 96.7) observed him/her open a new injection pack, and 7.4% (95% CI: 6.4 to 8.4) had seen a used syringe or needle near their home or community in the past 12 months. Men who had received ≥1 injection in the past 12 months (adjusted odds ratio, 3.2; 95% CI: 1.2 to 8.9) and women who had received an injection in the past 12 months, not for family planning purposes (adjusted odds ratio, 2.6; 95% CI: 1.2 to 5.5), were significantly more likely to be HIV infected compared with those who had not received medical injection in the past 12 months. Injection preference may contribute to high rates of injections in Kenya. Exposure to unsafe medical waste in the community poses risks for injury and infection. We recommend that community- and facility-based injection safety strategies be integrated in disease prevention programs.

Evolution of the Global Use of Unsafe Medical Injections, 2000–2010

ObjectiveSince 1999, substantial efforts have been made by the international community to reduce the risks associated with unsafe injections, through ministries of health, international donors, the World Health Organization and the Safe Injection Global Network. The present study attempted to measure the progress, or lack thereof, made over the 2000–2010 decade in reducing unsafe injections in ten regions of the world corresponding to developing and transitional economies.MethodsData about the number of injections per person per year and the proportion of re-use of syringes and needles were obtained for 2010, mainly from population surveys, and compared with previous estimates for 2000 which had used various sources of information including injection safety assessments, population surveys and published studies on injection practices.ResultsFrom 2000 to 2010, in developing countries and transitional economies, the average number of injections per person per year decreased from 3.40 to 2.88, while the proportion of re-use of injection devices dropped from 39.8% to 5.5%. Combining both factors the number of unsafe injections per person per year decreased from 1.35 to 0.16. Even if substantial progress has been made, the Eastern Mediterranean region remains problematic, with 0.57 unsafe injections per person per year. In sub-Saharan Africa and Latin America, people now receive on average only 0.04–0.05 unsafe injections per year.ConclusionSubstantial progress has been made in reducing the number of unsafe injections in developing countries and transitional economies, essentially through a reduction in the re-use of injection devices. In some regions, elimination of unsafe injections might become a reasonable goal.

Estimating the burden of disease from unsafe injections in India: A cost-benefit assessment of the auto-disable syringe in a country with low blood-borne virus prevalence

Background:Unsafe medical injections are a prevalent risk factor for viral hepatitis and HIV in India.Objectives:This review undertakes a cost–benefit assessment of the auto-disable syringe, now being introduced to prevent the spread of hepatitis B virus, hepatitis C virus, and human immunodeficiency virus (HIV).Materials and Methods:The World Health Organization methods for modeling the global burden of disease from unsafe medical injections are reproduced, correcting for the concentrated structure of the HIV epidemic in India. A systematic review of risk factor analyses in India that investigate injection risks is used in the uncertainty analysis.Results:The median population attributable fraction for hepatitis B carriage associated with recent injections is 46%, the median fraction of hepatitis C infections attributed to unsafe medical injections is 38%, and the median fraction of incident HIV infections attributed to medical injections is 12% in India. The modeled incidence of blood-borne viruses suggests that introducing the auto-disable syringe will impose an incremental cost of $46–48 per disability adjusted life year (DALY) averted. The epidemiological evidence suggests that the incremental cost of introducing the auto-disable syringe for all medical injections is between $39 and $79 per DALY averted.Conclusions:The auto-disable syringe is a cost-effective alternative to the reuse of syringes in a country with low prevalence of blood-borne viruses.

Uncovering high rates of unsafe injection equipment reuse in rural Cameroon: validation of a survey instrument that probes for specific misconceptions.

BackgroundUnsafe reuse of injection equipment in hospitals is an on-going threat to patient safety in many parts of Africa. The extent of this problem is difficult to measure. Standard WHO injection safety assessment protocols used in the 2003 national injection safety assessment in Cameroon are problematic because health workers often behave differently under the observation of visitors. The main objective of this study is to assess the extent of unsafe injection equipment reuse and potential for blood-borne virus transmission in Cameroon. This can be done by probing for misconceptions about injection safety that explain reuse without sterilization. These misconceptions concern useless precautions against cross-contamination, i.e. "indirect reuse" of injection equipment. To investigate whether a shortage of supply explains unsafe reuse, we compared our survey data against records of purchases.MethodsAll health workers at public hospitals in two health districts in the Northwest Province of Cameroon were interviewed about their own injection practices. Injection equipment supply purchase records documented for January to December 2009 were compared with self-reported rates of syringe reuse. The number of HIV, HBV and HCV infections that result from unsafe medical injections in these health districts is estimated from the frequency of unsafe reuse, the number of injections performed, the probability that reused injection equipment had just been used on an infected patient, the size of the susceptible population, and the transmission efficiency of each virus in an injection.ResultsInjection equipment reuse occurs commonly in the Northwest Province of Cameroon, practiced by 44% of health workers at public hospitals. Self-reported rates of syringe reuse only partly explained by records on injection equipment supplied to these hospitals, showing a shortage of syringes where syringes are reused. Injection safety interventions could prevent an estimated 14-336 HIV infections, 248-661 HBV infections and 7-114 HCV infections each year in these health districts.ConclusionsInjection safety assessments that probe for indirect reuse may be more effective than observational assessments. The autodisable syringe may be an appropriate solution to injection safety problems in some hospitals in Cameroon. Advocacy for injection safety interventions should be a public health priority.

“I Can’t Use a Condom, I Am a Christian:” Salvation, Death, and… Naivety in Africa

The countries of the Southern African Development Community – Angola, Botswana, Democratic Republic of the Congo, Lesotho, Madagascar, Malawi, Mauritius, Mozambique, Namibia, Seychelles, Swaziland, South Africa, Tanzania, Zambia, and Zimbabwe – continue to be hardest hit by the HIV and AIDS pandemic. There is a whole range of social, biological, economic, and political factors responsible for such a situation. In most of the countries of the Southern African region, HIV infection prevalence estimates among adults are beyond 10%; and even higher in young women, especially pregnant ones. Besides being a consequence of AIDS, malnutrition contributes to HIV vulnerability, further deteriorating HIV infection. The common mode of HIV spread in Africa is heterosexual intercourse, as opposed to the Americas and Eastern Europe, where injecting drug use and male homosexual intercourse are the common mode. The extent of the contribution of heterosexual intercourse to the spread of HIV in Africa is not accepted by all medical scientists across the world. Gisselquist et al have suggested that the role of unsafe medical injections in the transmission of HIV within the health sector has been underestimated (1). This observation has been corroborated by other researchers (2,3). Lopman et al, however, have not found sufficient evidence to support the suggestion that medical injections could contribute the HIV infection in Zimbabwe (4).

Minimum infective dose of HIV for parenteral dosimetry

The probability of HIV-1 transmission in a small blood exposure such as a needlestick injury or an unsafe medical injection has been estimated indirectly. Now that several comparable laboratory simulations have provided data on inoculum volumes for such exposures, the epidemiological evidence supporting these estimates can be validated and qualified using dosimetry. This review of data on infective titre, viral load and injection inoculum volume compares three approaches to HIV dosimetry. Agreement across the three approaches indicates that unsafe medical injections are several times more likely to transmit HIV-1 than needlestick accidents, and that the risk remains substantial if injection equipment is wiped, rinsed or flushed prior to re-use. The 50% infective dose of HIV in blood exposures ranges from one virion (two copies RNA) in primary infection with CCR5 co-receptor using strains of HIV-1 to 65,000 copies HIV-1 RNA in blood from an asymptomatic source patient. The median transmission risks for unsafe intravenous or intramuscular injections using equipment cleaned but not sterilized after use on a symptomatic pre-AIDS patient are 1.8% (95% confidence interval [CI] 0.1-3.2%) and 0.8% (95% CI 0.1-1.4%), respectively.

Injection risks and HIV transmission in the Republic of South Africa

The sexualization of the HIV epidemic in South Africa has been used as evidence that unsafe medical injections are of minimal importance to transmission in Africa, because the country was thought to be free of unsafe injection risks. More recent observation reveals routine failures in infection control in South African maternity and paediatric wards and in public dental clinics. In one province at least one medical injection in five is administered with a used needle or syringe. Over 25% of new HIV infections identified in South African adults using the BED IgG capture enzyme immunoassay in 2005 were in individuals reporting they had not been sexually active in the past 12 months. Immunization injections received at public health facilities are associated with HIV infections in children, many of whom may have passed HIV to their mothers during breastfeeding. South Africa is one of few countries in sub-Saharan Africa not using auto-disable (non-reusable) syringes for all immunizations. Using resource scarcity as justification for needle reuse is ethically indefensible, as injection safety is a readily achievable goal.

Increase in clinical prevalence of AIDS implies increase in unsafe medical injections

A mass action model developed by the World Health Organization (WHO) estimates that the re-use of contaminated syringes for medical care accounted for 2.5% of HIV infections in sub-Saharan Africa in 2000. The WHO's model applies the population prevalence of HIV infection rather than the clinical prevalence to calculate patients' frequency of exposure to contaminated injections. This approach underestimates iatrogenic exposure risks when progression to advanced HIV disease is widespread. This sensitivity analysis applies the clinical prevalence of HIV to the model and re-evaluates the transmission efficiency of HIV in injections. These adjustments show that no less than 12-17%, and up to 34-47%, of new HIV infections in sub-Saharan Africa may be attributed to medical injections. The present estimates undermine persistent claims that injection safety improvements would have only a minor impact on HIV incidence in Africa.

Injection drug use, unsafe medical injections, and HIV in Africa: a systematic review.

The reuse of injecting equipment in clinical settings is well documented in Africa and appears to play a substantial role in generalized HIV epidemics. The U.S. and the WHO have begun to support large scale injection safety interventions, increased professional education and training programs, and the development and wider dissemination of infection control guidelines. Several African governments have also taken steps to control injecting equipment, including banning syringes that can be reused.However injection drug use (IDU), of heroin and stimulants, is a growing risk factor for acquiring HIV in the region. IDU is increasingly common among young adults in sub-Saharan Africa and is associated with high risk sex, thus linking IDU to the already well established and concentrated generalized HIV epidemics in the region. Demand reduction programs based on effective substance use education and drug treatment services are very limited, and imprisonment is more common than access to drug treatment services.Drug policies are still very punitive and there is widespread misunderstanding of and hostility to harm reduction programs e.g. needle exchange programs are almost non-existent in the region. Among injection drug users and among drug treatment patients in Africa, knowledge that needle sharing and syringe reuse transmit HIV is still very limited, in contrast with the more successfully instilled knowledge that HIV is transmitted sexually. These new injection risks will take on increased epidemiological significance over the coming decade and will require much more attention by African nations to the range of effective harm reduction tools now available in Europe, Asia, and North America.

How Important Are Unsafe Medical Injections in the Spread of HIV in Africa?

For the past decade HIV prevention efforts in most African countries have been predicated on the assumption that heterosexual intercourse is the predominant mode of HIV transmission among adults whereas mother-to-child transmission predominates in children. UNAIDS documents have routinely stated that 90% of adult infections are the result of heterosexual transmission and national AIDS control programs have emphasized behavioral risk reduction as the key to prevention. During the past 3 years however a small group of scientists led by David Gisselquist has questioned these assumptions publishing a series of articles--mostly in the International Journal of STD and AIDS postulating that unsafe medical injections may be responsible for the majority of HIV infections in sub-Saharan Africa. If true this would clearly have major implications for HIV control policies in Africa and beyond. (excerpt)

Simulations of the HIV Epidemic in Sub-Saharan Africa: Sexual Transmission Versus Transmission Through Unsafe Medical Injections

Heterosexual transmission has long been considered the predominant route of transmission of HIV-1 in sub-Saharan Africa. However, some have argued that unsafe medical injections account for the majority of transmission in this region. The goal of this study was to compare the HIV-1 epidemics associated with different transmission routes. An age-structured deterministic compartmental model of HIV-1 transmission through both sexual contact and unsafe injections was developed and simulations of sexual transmission and iatrogenic transmission were compared with observed prevalence. Iatrogenic transmission probabilities and numbers of unsafe injections required to generate observed prevalence are unfeasibly high. Simulations of sexually transmitted HIV-1 generate observed prevalence using transmission probabilities and average partner change rates that are within plausible bounds. Heterosexual transmission seems a more likely route of transmission in the region. However, heterogeneity in contact patterns is of key importance. Further information on groups who are likely to receive more injections is required.

Pediatric HIV infection.

The present cross sectional study was undertaken to study clinical profile of HIV infection in children in Northern India. 64 children from newborn to eighteen years, presenting for confirmation of diagnosis of HIV infection or monitoring of CD4-CD8 counts in confirmed cases, were evaluated. Children were categorized as per CDC classification of Pediatric HIV. The diagnosis was confirmed by serological tests or PCR assay. CD4-CD8 counts were done by FACS Count. Majority of the children were between 18 months to 5 years. Adolescents comprised 24% of the case. 51.5% children were infected through the mode of mother to child transmission. 39% of the case was transfusion-mediated. Unsafe medical injections probably contributed to 6.2% and heterosexual promiscuity led to 3.1% cases. Clubbing, not described in Indian studies so far, was seen in 9.3% cases. HIV infection is a chronic childhood disease extending into adolescence, and contaminated blood and unsafe medical injections are still important routes of HIV transmission in India.

Association between medical injections and HIV infection in a community-based study in India

It has been proposed that unsafe medical injections may account for a substantial proportion of HIV infections in developing countries, contrary to the conventional wisdom that heterosexual HIV transmission is largely responsible for the speed and trajectory of the HIV epidemic [1–5]. For example, it has been argued that the declining rates of HIV infection in Uganda are the result of improvements in injection safety and not increased rates of condom use or other changes in sexual behaviour [6]. However, a study in rural Rakai district in southwestern Uganda [7] did not demonstrate a significant association between medical injections and the acquisition of HIV. It is estimated that over 50% of injections given in the developing world are unsafe [8]. A study of unlicensed medical practitioners in southern India [9] demonstrated that the contamination of medical injection paraphernalia is common. The unlicensed medical practitioners were frequently observed using unsterile syringes, reusing disposable syringes, and contaminating multidose medicine bottles through inappropriately flushing drawing needles with warm water. We examined this issue in the context of a community-based survey in rural southern India. Institutional Review Boards from the University of Manitoba, Winnipeg, Canada, and St John's Medical College, Bangalore, India, approved the study. We conducted the study in Bagalkot district, situated in the northern part of the Indian state of Karnataka. Cluster sampling was used to select 10 villages and 20 urban blocks randomly in three talukas (sub-districts) within Bagalkot, based on probability proportional to population size. After informed consent was obtained, 4949 individuals aged 15–49 years were interviewed between April and September 2003. Of these, 81% (4008 respondents: 1864 rural and 2144 urban) provided blood samples for HIV testing. Data on previous medical injections and other sociodemographic and behavioural factors were obtained through interviews. HIV infection was detected by enzyme-linked immunosorbent assay (ELISA); (Detect HIV 1/2; BioChem ImmunoSystems, Montreal, Canada), and confirmed by a second ELISA (Genedia HIV 1/2 ELISA 3.0; Green Cross Life Science Corporation, South Korea). Crude and adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated using the Stata statistical program. Overall, 95% of the respondents reported ever receiving a medical injection as an adult, either by a qualified medical doctor or a traditional medical practitioner. The mean number of injections received in the year before the study was 3.5. Rural women received an average of 4.1 injections in the year before the study, whereas rural men received 3.7 injections, and the average urban dweller received 3.4 injections. These differences were statistically significant (P < 0.05). Table 1 shows HIV positivity according to the previous history of medical injections, both lifetime and in the past year. Those who reported never receiving an injection during their adult lifetime had an HIV prevalence of 1.5%, compared with 2.96% among those who reported ever receiving an injection (OR 2.0, 95% CI 0.64–6.3). Logistic regression was used to study the association between medical injections and HIV infection, controlling for age, urban/rural residence, occupation, self-reported sexual risk behaviour, marital status, education level and caste, and the adjusted OR among individuals who had ever received an injection decreased to 1.59 (95% CI 0.49–5.16). Men reporting 10 or more injections, and women reporting five or more injections in the past year were more likely to be HIV seropositive than men or women reporting no injections in the past year, although adjusted OR were statistically significant only for women.Table 1: HIV prevalence and history of medical injections.Medical injections are common in India, and many of the injections may be unsafe. However, data from this study do not provide evidence for an association between HIV infection and medical injections. Although there was an association between reported high numbers of injections in the past year and HIV infection, particularly among women, temporal biases are likely, because those with HIV-related illnesses may receive more medical care and medical injections than those without HIV. There were no significant associations observed among women or men between HIV and a history of ever having received an injection as an adult. Limitations with these data include not having information on the indications for which the injection was given, the nature of the injections, or the setting (type of health facility or provider) in which the injection was given. Although we did not demonstrate an association between HIV and medical injections, HIV and other pathogens may clearly be transmitted by unsafe injections. It is still important therefore universally to promote safe, sterile injection practices as general health measures, and further studies are needed to explore the contribution of medical injections to the HIV epidemic in more detail.

Individual Level Injection History: A Lack of Association with HIV Incidence in Rural Zimbabwe

BackgroundIt has recently been argued that unsafe medical injections are a major transmission route of HIV infection in the generalised epidemics of sub-Saharan Africa.Methods and FindingsWe have analysed the pattern of injections in relation to HIV incidence in a population cohort in Manicaland in a rural area of Zimbabwe. In Poisson regression models, injections were not found to be associated with HIV in males (rate ratio = 0.33; 95% confidence interval: 0.07 to 1.46) or females (rate ratio = 1.04; 95% confidence interval: 0.59 to 1.85).ConclusionIt is important that unsafe medical injections can be confidently excluded as a major source of HIV infection. In rural Zimbabwe the evidence is that they can.

Estimating HIV-1 transmission efficiency through unsafe medical injections.

The transmission efficiency of HIV-1 through unsafe medical injections can be estimated from seroconversions among health care workers (HCWs) after percutaneous exposures and documented iatrogenic outbreaks. Data from a case-control study of seroconversion after percutaneous exposures among US and European HCWs shows an average rate of seroconversion after deep injuries - arguably comparable to unsafe injections - of 2.3%. Information from an iatrogenic HIV outbreak in a Romanian orphanage suggests a transmission efficiency of 2-7%. Even these estimates may be too low to explain the rapid spread of HIV among Russian and Libyan children in iatrogenic outbreaks discovered in 1988 and 1998, respectively. In countries in sub-Saharan Africa and elsewhere with high HIV prevalence and large numbers of unsafe injections, personal risk as well as the share of the HIV epidemic associated with unsafe injections may be an order of magnitude higher that many experts have supposed.