Results of our study showed that IDUs in Bangladesh are most vulnerable to acquisition and spread of HIV/AIDS among general population due to lack of awareness and knowledge about HIV/AIDS and practicing risky behaviors such as high level of needle/syringe sharing and unprotected sex. The majority of the IDUs in this study were young and middle-aged men. This may be due to the fact that females prefer taking injections and treatment at home instead of drug rehabilitation centers due to social stigma [6, 12]. The recent increase in shift to injection might result from easy availability of injecting drugs, relatively cheaper price compared to other drugs, and better surveillance and reporting [12, 13]. A previous study in Bangladesh reported 78% of IDUs continued stably exchanging needles and syringes, but the reported rate of condom use in commercial sex remained low, improving from only 7.8% to 17.7% [14, 15]. Other studies in Bangladesh among IDUs also reported risky sexual behaviors among IDUs compared to non-IDUs [16, 17].

Another study among 505 “drug addicts” in Dhaka showed those who were HIV positive (3.7%) were mainly IDUs, and all of them shared needles. The majority of the participants (73.3%) of our study also reported sharing needles. Those drug users with HIV were also more likely to report unprotected sex (76.4%), having multiple sex partners (87.1%), and the presence of STIs (64.2%) [14]. These reports are consistent with our findings.

The results of our study showed low awareness about the consequences of drug use and about HIV, which is consistent with previous studies [18–20]. In general, most IDUs have heard of HIV/AIDS but they are unaware of how it spreads by injecting drugs. A marker for prevalent injection drug use is the prevalence of hepatitis C [16]. In Dhaka the prevalence of hepatitis C declined significantly over the years, which showed that safer injection practices are being adopted [4]. Early intervention efforts in Bangladesh, including extensive NEPs, are estimated to have reduced infections among IDUs and also contributed to decrease of the transmission to other populations [21]. However, these studies have been conducted among selected population groups and intervention subjects and do not represent the general IDUs in the country.

It is reported that the HIV epidemics of several other countries in Asia started off in IDUs and then spread via needle sharing and unprotected sex with the sex workers and thereafter to the general population [22]. In China, nearly half of all people infected with HIV are believed to have become infected through injecting drug use. There is often an overlap between communities of IDUs and communities of sex workers in many parts of Asia, as those who sell sex may do it to fund a drug habit, or they may have been involved in sex work first before turning to drug use [23]. In Bangladesh, around 75% of IDUs reported having unprotected sex in their last sexual encounter with a commercial sex worker [15]. Previous reports from Bangladesh showed that female IDUs are particularly vulnerable, as most of them reported selling sex to support their addiction and depended on their male partners to buy their drugs and shared needles with them [24]. Another study in Bangladesh reported that among female IDUs 61% reported selling sex [6]. In our study, of the 11 female participants, none reported any self-income or occupation as sex worker.

HIV can spread extremely rapidly among IDUs sharing needles, and IDUs provide a “bridge” for HIV transmission to their sexual partners and children. One approach has been to attempt to reduce drug use by strengthening drug interdiction and enforcement policies [25]. However, such policies are not necessarily effective in controlling the drug supply; they may simply reroute drug trade elsewhere, and they may indirectly result in raising risky behavior that spreads HIV.

The Narcotics Control Act (1990) of Bangladesh made drug use a criminal offense and drug users criminals and called for mandatory treatment of drug users. The act gave law enforcement agents control over drug sales and use and provision for harassment of drug sellers and users. However, the National AIDS Policy and the National HIV/AIDS Strategic Plan incorporated harm reduction services for IDUs in its strategic plan and law reform remains an urgent need in order to facilitate intervention activities with drug users.

There is a need to understand the barriers as well as the facilitators for NEPs among IDUs in order to improve health seeking behavior and awareness. Our data showed that a great majority of the participants did not know where to seek treatment, considered treatment too expensive, and were willing to use NEPs. Thus, efforts to promote NEPs through government funded programs and creating awareness among the IDUs in Bangladesh are needed. The keys to reducing the rapid spread of HIV/AIDS among IDUs are, first, recognition of injecting drug use as a potential problem and, second, early intervention that includes harm reduction and drug treatment [26, 27]. Evidence shows that IDUs do change their risky injecting behavior as a result of harm reduction programs and sometimes without large-scale intervention efforts [2, 27]. The two important components for harm reduction programs are education and provision of the means with which to change behavior. The latter may include sterile needles (through either NEPs or availability in pharmacies without a prescription), bleach, and/or drug rehabilitation programs. Interventions to prevent sexual transmission from IDUs to their partners through increased condom use have met with only limited success but are vital for preventing the spread of HIV out of the injecting group and into the general population [28].

The WHO defined a comprehensive package of nine interventions for IDUs, of which the following four have evidence for effectiveness in reducing HIV incidence: needle and syringe programs (NSP), medication-assisted therapy (MAT), antiretroviral therapy (ART), and HIV counseling and testing (HCT) [2]. At least 60% coverage is likely to be required to reduce HIV incidence. Evidence from LMIC contexts suggests that NSP and MAT can reduce high-risk injecting behavior, HCT can reduce risky sexual behavior, and ART can plausibly have preventive benefit among IDUs for onward parenteral transmission with clearer evidence that antiretroviral therapy (ARV) can prevent onward sexual transmission. Modeling analysis suggests that, compared with current low coverage, a scale-up of these four interventions in combination would be a beneficial and cost-effective approach [2].

Despite several risk factors, the HIV/AIDS prevalence in Bangladesh remains considerably low, which might be due to the early interventions by the government and several NGOs, targeted at most at risk populations. Previous studies in Nepal and Indonesia have reported that HIV prevalence among IDUs remained low for several years but then increased to over 45% [2]. These studies also highlight the importance of early interventions in the epidemic. However, currently the coverage of interventions for IDUs is inadequate in Bangladesh [29]. While the response to date has reduced the level of HIV transmission and ensured many people living with HIV (PLHIV) were under NEP coverage and received treatment [30], sufficient justification exists on human rights and public-health grounds for scaling up evidence-based prevention of HIV infection among IDUs. Social and structural changes for a combination intervention approach for HIV/AIDS prevention are essential. Bangladesh still has a rare window of opportunity to prevent significant HIV epidemic by providing prevention service to those at most risk of HIV infection including IDUs.