Epidemiology of Hepatitis C Virus Infection Among High-risk Populations in Northeastern Iran

According to the World Health Organization (WHO) estimation, 58 million people are chronically infected with Hepatitis C virus (HCV). Approximately 1.5 million persons are infected with this virus every year, and 290,000 persons die from hepatitis C complications such as cirrhosis and liver cancer (1). The highest HCV infection prevalence has been reported among the general population of the WHO Eastern Mediterranean Region (2.3%) and European Region (1.5%) (2).

Compared to other countries in the Eastern Mediterranean Region and the world, Iran is considered a country with a very low anti-HCV seropositivity (0.3 - 0.6%) among the general population (3, 4). It is assumed that strict HCV screening of donated blood units since 1996, performing harm reduction programs for people who inject drugs (PWID), the early finding of HCV-seropositive individuals, and treatment of the patients with the low-cost generic direct-acting antiviral drugs are the most critical factors associated with the lower rate of this infection in Iran (3). On the other hand, much higher rates of HCV infection were estimated among Iranian populations at intermediate to high risk of exposures such as PWID (41 - 47%) (5-7), prisoners (22 - 28%) (6, 8, 9), hemodialysis patients (11%) (10), people who use but not inject drugs (8%) (6, 7), female sex workers (8%) (6), and homeless children (2%) (11).

Previously, we demonstrated a low HCV infection prevalence (0.4%) among the general population of Mashhad, the capital city of the Razavi Khorasan province, northeastern Iran (12). However, evidence regarding the epidemiology of this infection among the HCV at-risk population is limited in this region. In a recent brief survey, we detected 12.8% of HCV viremia among 390 persons referred to drug treatment centers in Mashhad (13).

To assess HCV infection prevalence and the related risk factors among high-risk populations, especially people who use drugs (PWUD) outside of prison in northeastern Iran.

In this cross-sectional study, 962 persons in Razavi Khorasan province were recruited from August 2018 to the end of January 2022. They included PWUDs referred to eight drug treatment and harm reduction centers in Mashhad and Gonabad cities, and individuals with a history of crimes such as drug use or imprisonment who worked in a private industrial unit in Mashhad. All these centers were selected based on a non-random sampling method.

The demographic characteristics and risky medical history and behaviors were evaluated. The presence of serum anti-HCV antibodies was assessed using rapid test kits (SD Bioline HCV, South Korea). HCV viral genomes were extracted from seropositive samples (DynaBio, Takapouzist, Iran or RNJia Virus Kit, ROJETechnologies, Iran), and single-step reverse transcriptase or qualitative real-time polymerase chain reactions (Novin Gene, AmitisGen, Iran) was used to confirm the infection. The serum levels of alanine transaminase (ALT) and aspartate transaminase (AST) were measured using an autoanalyzer (Mindray, USA) among HCV RNA-positive samples.

Data were analyzed using chi-square and t-test and SPSS Windows software (version 19.0, IBM Corp., Armonk, NY, USA). Besides, logistic regression analysis was used to discover variables that predicted the existence of HCV RNA in the serum samples. Odds ratios (ORs) with 95% confidence intervals (CI) were calculated, and P-values of less than 0.05 was statistically significant.

A total of 707 males and 255 females with a mean age of 39.8 ± 10.2 years were enrolled. Anti-HCV antibodies were detected in 13.41% (129/962, 95% CI 11.26 - 15.56%), of which 117 samples were available for polymerase chain reaction (PCR) testing. HCV viral genome was detected in 88 cases (75.2%); the total HCV viremia rate was calculated as 9.26% (88/950, 95% CI 7.42 - 11.11%). The elevated serum concentrations of the enzymes aspartate transaminase and alanine transaminase (> 40 IU/mL) were identified in 31.33% (26/83) and 48.19% (40/83) of the HCV RNA positive patients, respectively.

The variables associated with HCV infection were evaluated among some people who were referred to the drug treatment centers. At the time of the survey, most responders were employed (61%, 332/544), married (44.9%, 244/544), and illiterate or with an education level of elementary school (45.7%, 236/516). Furthermore, history of imprisonment, tattooing, drug injection, and blood transfusion was declared by 65.42% (314/480), 41.88% (227/542), 17.44% (116/665), and 13.90% (73/525) of responders, respectively. As Table 1 shows, HCV viremia was significantly associated with the older age (P < 0.001), male sex (P = 0.03), being unemployed (P = 0.009) or single (P < 0.001), and a history of blood transfusion (P = 0.003), tattooing (P < 0.0001), drug injection (P < 0.0001), and incarceration (P < 0.0001). Logistic regression analysis showed that HCV viremia was significantly associated with the older age (P = 0.002), being single (P = 0.009, OR = 2.50, CI 95%: 1.25 - 4.99), and history of drug injection (P < 0.001, OR = 5.05, CI 95%: 2.60 - 9.80) or incarceration (P = 0.04, OR = 2.74, CI 95%: 1.04 - 7.19). On the other hand, no significant association was observed between HCV infection and participant’s gender (P = 0.49, OR = 0.75, CI 95%: 0.33 - 1.71), employment status (P = 0.49, OR = 1.27, CI 95%: 0.65 - 2.48), and a history of blood transfusion (P = 0.20, OR = 1.70, CI 95%: 0.76 - 3.80), or tattooing (P = 0.06, OR = 1.90, CI 95%: 0.99 - 3.67).

The present study shows that 13.4% of the individuals with a history of drug use in northeastern Iran have serological markers of HCV exposure, 9.3% have detectable HCV RNA, and are currently infected with this virus. Furthermore, the HCV viremia rate among the population with drug injection history (44.0%) was significantly higher than that among those without such a history (6.2%). These proportions are much higher than reported previously for anti-HCV seropositivity and viremia (0.67% and 0.42%, respectively) among the general population in this area (12).

The findings of HCV prevalence among people who use or inject drugs were consistent with the earlier data estimated at the national level in Iran. Malekinejad et al. systematically reviewed 24 eligible reports on the prevalence of HCV infection among drug-dependent people outside of prison in Iran. They estimated that the overall HCV seropositivity was 8% among persons who reported no history of drug injection and 45% among participants with such a history (7). Another systematic review estimated an HCV prevalence of 16.2% among substance-dependent individuals and 41.3% among PWID in Iran (6). Individuals who use drugs, especially those with a history of injection, are generally considered populations at high risk of HCV exposure. It is expected that using a piece of shared equipment for the injection is associated with a higher risk of HCV acquisition among PWID (5). The higher HCV prevalence rates among non-injecting PWUD might be attributable partly to misclassification of PWID as non-injecting PWUD (14, 15); however, sharing of non-injection equipment as well as other risky behaviors such as tattooing and unsafe sex could be a possible route of the virus transmission in this population (15).

It is estimated that the serological markers of HCV infection are detectable on average in 60% of PWID in the world (16). Furthermore, Scheinmann et al. systematically reviewed 28 published studies and identified that HCV prevalence in self-reported non-injecting PWUD ranged from 2.3 to 35.3%, with a median of 14%. They concluded that HCV prevalence among this group was larger than in a population who did not use drugs (15). Correspondingly, nearly half of PWID in the Middle East and North Africa have ever been exposed to this virus (17, 18). However, the prevalence rates broadly varied (22–94%) in different countries in this region (18). A high burden of HCV infection has also been estimated in other regions of the world. In Latin America and the Caribbean, pooled regional anti-HCV seropositivity was reported as 49.0% in PWID; however, a much lower rate (3.6%) was estimated in non-injecting PWUD (19). Likewise, a systematic review of 40 reports estimated the high rates of anti-HCV seropositivity in both PWID (67.0%) and non-injecting PWUD (18.3%) in China (20).

The findings suggested that HCV infection prevalence among PWUD with a history of imprisonment was higher than those who did not report such a history (21.1% and 3.6%, respectively). Similarly, recent systematic reviews estimated higher pooled rates of HCV prevalence among PWID who resided some time in prison (52 - 58%) versus those who had no history of incarceration (44 - 45%) (5, 7). On the other hand, we could not find a significant association between HCV infection and tattooing in regression analysis; however, the probability value was close to the statistical significance level. Many researchers in Iran and other countries concluded that unsafe skin-piercing procedures such as tattooing effectively transmit HCV infection. This transmission can occur particularly among HIV-infected individuals, PWID, substance-dependent people who do not report drug injection, prisoners, and even low-risk populations such as the general population and blood donors (4, 21). Behzadifar et al. estimated that prisoners with a history of tattooing had a significantly higher HCV risk than other inmates (OR = 2.6) (8). Likewise, Jafari et al. estimated higher HCV frequency among non-injecting drug-dependent people with a history of tattooing than those without such a history (OR = 5.7) (22).

One of our study limitations is that we assessed the serum levels of liver enzymes only among patients with confirmed HCV infection, and therefore, we could not compare these results between HCV RNA-positive and HCV RNA-negative groups.