In our national bio-behavioral study across 33 prisons, we found that approximately about 7% of people in prisons in Iran had a high self-perception of risk for HIV acquisition. A number of demographic factors (e.g., younger ages and not being married), behavioral factors (e.g., history of being in prison and receiving opioid agonist therapy), and sexual factors (e.g., condomless sex in the last sex, lifetime history of STI symptoms, and same-sex relationships in men) were significantly associated with higher odds of HIV self-perceived risk. Moreover, about 4 in 5 participants reported at least one HIV-related risky behavior, while a minority had a high self-perceived risk for contracting HIV.

Our study revealed a low prevalence of high self-perceived HIV risk among people in prisons in Iran, with only one in 15 reporting a high-risk perception. While comparisons with regional studies are limited due to scarce evidence from the Eastern Mediterranean region, our findings are comparable with a study in Scotland, where 12.4% and 7.3% of people in prisons had a medium and high self-perception of risk for HIV acquisition, respectively [18]. However, these estimates contrast sharply with studies from the USA, where an estimated 78.2% of 855 people in prison had a significantly higher self-perceived HIV risk [19]. Several factors, including cultural, social, and healthcare system differences between Iran and the USA, likely influence this disparity. In liberal high-income settings, HIV awareness is promoted through public health campaigns, and individuals may have more access to HIV-related information and prevention resources. In Iran, however, the relatively lower level of HIV awareness, socio-cultural stigma around HIV testing, and limited funding and staffing allocated to HIV education in prisons may contribute to a lower perceived risk of acquisition among people in prisons. To address this low-risk awareness in Iranian prisons, implementing targeted interventions, including comprehensive HIV education, increased access to sterile tattooing and injection equipment, routine HIV testing, and peer education programs are warranted.

Our analysis of demographic variables showed that people under 30 years of age and those who were unmarried had significantly higher odds of perceiving themselves at high risk for HIV acquisition. These findings align with a cross-sectional study of 826 HIV-negative men in prisons in the USA, which demonstrated that younger age was associated with higher self-perceived HIV risk [19]. The elevated risk perception among younger and unmarried individuals may be attributed to their higher engagement in risky behaviors. For instance, a study on Iranian people in prisons found that those aged 18–29 and single individuals had significantly higher odds of non-injection drug use in the month prior to being in prison [20]. Furthermore, the prevalence of lifetime tattooing among people in prisons in Iran during 2015–2016 was higher in those under 35 compared to those 35 and older [21]. These patterns of risk behavior among younger and unmarried people in prisons likely contribute to their increased self-perceived HIV risk, underscoring the need for targeted interventions for these demographic groups within the prison population.

We also found that several behavioral factors were significantly associated with high self-perceived HIV risk among people in prisons. These included prior imprisonment, lifetime drug use or injection, tattooing, same-sex sexual practices among men, condomless sex, and STI symptoms. Interestingly, while previous studies in the USA have found that pre-incarceration HIV testing and drug use were associated with lower self-perception of the risk of HIV amongpeople in prisons [19], our study showed no significant association with HIV knowledge. However, we found that lifetime drug use significantly increased the odds of high self-perceived risk. The link between risky behaviors and self-perceived risk is further supported by evidence that individuals with a history of tattooing in prison have a higher prevalence of drug use, injection, and non-primary sexual partners [21]. Moreover, same-sex intercourse among men, especially without consistent condom use, is associated with higher HIV transmission rates, likely contributing to increased risk perception. Notably, we observed similarities between factors influencing self-perceived HIV risk and those affecting HIV testing uptake, suggesting potential synergies in interventions targeting both outcomes. Our finding that STI-related symptoms were associated with 2.18 times higher odds of high self-perceived HIV risk aligns with a previous study among Iranian people in prisons, which also found a significant association between STI symptoms and self-perceived HIV risk [15]. These findings collectively underscore the complex interplay of behavioral factors influencing HIV risk perception in prison populations and highlight potential targets for intervention.

We also observed a significant gap between actual HIV risk behaviors and self-perceived risk among people in prisons in Iran, with ~ 80% reporting at least one HIV-related risky behavior. We also noted a positive association between the number of risky behaviors and self-perceived HIV risk, with 8.4% of individuals engaging in more than one risky behavior reporting high-risk perception. While this may suggest some awareness of the cumulative impact of multiple risk factors, the overall low percentage is concerning, even among those with multiple risk behaviors. In contrast, a study of 501 HIV-negative men with harmful alcohol use reported a 30.9% prevalence of high self-perceived HIV risk [22], potentially due to increased awareness from targeted interventions or increased media exposure in that specific population. The disparity between our findings and those from other high-risk populations may be attributed to several factors. Cultural norms and societal stigma surrounding HIV in the conservative context of Iran may lead individuals, particularly in high-risk groups, to underestimate their vulnerability due to fear of discrimination [24,25,25]. Additionally, substance use can impair judgment, leading to high-risk behaviors without full acknowledgment of consequences [26], and may reduce engagement with educational or preventive interventions. These findings underscore the need for interventions that address cultural, societal, and individual influences on HIV risk perception to enhance prevention strategies. In the Iranian context, leveraging mass media as the primary source of HIV knowledge [27] could be particularly effective in improving risk awareness and prevention efforts among people in prisons.

We acknowledge the limitations of our study. First, we did not assess the sexual orientation of participants, as this could be a sensitive topic inside Iranian prisons. Second, other data, such as information on condom use, STI symptoms, having same-sex practice among men, and age at first sexual intercourse, were self-reported and thus subject to potential recall, reporting, and social desirability biases. These biases could have led to underreporting of high-risk behaviors. Moreover, social desirability bias may have influenced participants to report lower self-perception of HIV risk, particularly in a stigmatized prison environment. Variations in prison types, regional differences, and the diversity in incarceration conditions across Iran may affect the external validity of our results. Lastly, this was a cross-sectional study, making it challenging to determine the direction of the association and draw causal conclusions about the observed associations. Despite these limitations, our study has several strengths. It is one of the largest nationwide surveys conducted in Iranian prisons, offering robust data on self-perception of risk for HIV acquisition and its correlates in this understudied population. Using a multistage random sampling approach and face-to-face interviews enhanced the reliability and generalizability of the findings. Future research should explore longitudinal designs to better understand the causal pathways of risk perception and behavior. In addition, integrating methods to minimize biases, such as inclusion of peer interviewers, could improve data accuracy in future studies. Furthermore, using qualitative methods could provide deeper insights into the contextual and cultural factors influencing self-perception of risk for HIV acquisition among people in prisons.