Waste produced in the course of healthcare activity carries a high potential for infection, and its poor management poses direct and indirect health risks to health care workers (e.g., doctors, nurses, and laboratory workers), waste handlers, and patients in hospitals [1]. Medical waste contains wide range of pathogens such as human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) [2]. According to the World Health Organization, around 500 million people worldwide are chronically infected with either HBV or HCV. An estimated 1 million people die each year from causes related to viral hepatitis, most commonly liver disease, including liver cancer. About 57% of cases of liver cirrhosis and 78% of cases of primary liver cancer result from HBV and HCV infection [3]. A varying prevalence of HBV has been documented in different regions of the world; China, South-East Asia, sub-Saharan Africa, most Pacific Islands, and the Amazon basin are most affected. The prevalence of HBV infection in Africa is on average more than 10%, classifying the region as one of high endemicity for HBV [4,5].

HBV is more infectious than other blood-borne viral pathogens and is about 100 times more infectious than HIV. The infectiousness of HBV is partly explained by its higher viral load in the blood, longer viability in the environment (>7 days at room temperature), and transmissibility in the absence of visible blood [6]. Consequently, HBV presents the greatest occupational risk to non-immune health care workers (HCW) [7]. The seroprevalence of hepatitis B surface antigen (HBsAg) among HCW was reported to be 8.1% in Uganda [8] and 9.7% in Ethiopia [9]. It was also reported that medical waste handlers (MWH) are more exposed to HBV infection than other HCW [10], non-medical waste handlers (NMWH) [11,12], or the general population [6]. Indirect inoculation through improperly collected and/or segregated sharp materials is considered to be an occupational hazard for MWH in health institutions, compared to NMWH or the proportion of the general population that has no direct or indirect contact with medical waste [6,12].

Despite the availability of antiviral agents to treat chronic hepatitis, treatment policies are lacking in Ethiopia, and these drugs are inaccessible and very expensive. Therefore, prevention remains of crucial importance. In this regard, appropriate utilization of personal protective equipment (PPE), screening at the time of employment, and vaccinating susceptible individuals at increased risk of infection are direly needed. However, the government still lacks a policy for pre-employment vaccination and post-exposure prophylaxis against HBV for HCW at higher risk of exposure to blood and body fluids [12]. Evidence is scarce concerning the rate of exposure to HBV and HCV infection and potential risk factors among MWH in Ethiopia. Therefore, this study aimed to assess the rate of exposure to HBV and HCV infection, and associated risk factors, in MWH at three government hospitals in southern Ethiopia. Evidence from this study may be presented to public health officials, decision-makers, and other concerned bodies in order to plan possible intervention measures.

Occupational risk related to hepatitis virus exposure is a major concern for MWH in developing nations where a guideline for waste handling is not strictly followed. In this study, the prevalence of HBsAg, anti-HBc and anti-HCV in MWH was 1.3%, 39.4%, and 0.7%, respectively. MWH had a significantly higher rate of lifetime exposure to HBV infection compared to NMWH. The rate of HBV exposure was also shown to increase with age, such that participants older than 40 years had the highest rate of infection. In addition, MWH working in a hospital laundry were about ten-fold more likely to be exposed to HBV infection compared to others working in hospital wards. None of the other risk factors examined was found to influence the rate of HBV exposure.

The sero-prevalence reported in our study is in line with studies conducted among MWH in Tripoli, Libya that reported 2.3% prevalence of HBsAg (but also reported a higher rate of anti-HCV at 2.7%) [13] and in Palestine that reported 1.59% prevalence for HBsAg [14]. In contrast, higher rates have been reported in studies in Addis Ababa, central Ethiopia (6.3% for HBsAg) [11] and in Gondar, northwest Ethiopia (6% for HBsAg), although no difference was observed with respect to the rate of anti-HCV (1%) [12].

The significantly higher rate of lifetime exposure to HBV infection among MWH in comparison with NMWH in the current study this is in agreement with a study conducted in Addis Ababa [11] where MWH had 1.5 times the rate of exposure of NMWH. Moreover, MWH older than 40 years of age were also at increased odds of exposure to HBV infection in previous studies [11,13,15]. This increase with age may be due to the increased risk of exposure to HBV infection with time. The preponderance of HBV exposure among MWH based in hospital laundries may be due to the higher risk of contact with blood and other body fluids while handling contaminated materials.

Participants in our study who had tattoos or who had multiple sexual partners appeared to be at increased risk of lifetime exposure to HBV infection; however, this difference was not statistically significant after adjusting for other associated variables. Likewise, a trend towards a higher rate of HBV exposure among males compared with females was observed, but this was also not statistically significant. MWH with greater than 10 years of service appeared to be more affected by HBV compared to those with 1 years to 5 years of service, although the difference was not statistically significant. Previous studies of HCW indicate that the risk of exposure to HBV infection increases with longer service years [10,11,16,17].

Several other factors, such as prior blood transfusion, needle stick injuries, lack of training in infection prevention, and not being vaccinated, have been reported to increase the risk of HBV infection [15-19]. However, none of these associations was evident in our study. These days, most of the local blood bank centers screen blood for infections such as HIV, HBV, and HCV to prevent transfusion-transmitted infections. However, the frequent occurrence of sharp injuries among most MWH in the current and previous studies [16-20] highlights the need to give due attention to reducing such incidents. Causes of sharps injuries include improperly discarded sharps, improper handling of sharps during transportation, and handling over-filled sharps containers [21]. Improper disposal of sharps may be due to inadequate training, supervision, and support with regard to infection control and effective waste disposal practice provided to MWH. Resource shortages and workload pressures may also contribute to the failure to ensure the proper disposal of hazardous waste.

In this study, blood and other body fluids were involved in 11.2% of mucosal exposures within the last 12 months. This is significantly lower than the studies conducted in Addis Ababa (67.5%) [19], Gondar (64%) [22], Uganda (41%) [8] and Iran (86%) [23]. This disparity is perhaps due to differences in the sites of exposure: mouth, nose, eye and non-intact skin were considered in our study, while other studies also included intact skin on the hands and legs. Moreover, underreporting of exposures may result from employees’ fear of reprisal and job discrimination, or from recall bias.

Protective measures such as puncture-resistant sharps containers and extensive training and supervision for MWH on appropriate utilization of PPE such as gown, gloves, mask, apron, boots, and eye protection may reduce the incidence of sharps injuries and splash exposures. However, this key worker group will remain at risk until there is further improvement in the standards of waste segregation and disposal by healthcare professionals [21]. In this study, compliance with universal precautions was relatively high compared to other studies [12,17], but the frequent occurrence of sharps injuries and splash exposures indicates the inadequate utilization of PPE and highlights the need to strengthen training and supervision.

In this study, 39.4% of MWH were exposed to HBV infection; 22.4% of these developed protective immunity. However, the majority (58.9%) remained susceptible to infection and could potentially benefit from vaccination. Vaccination coverage was very low (7.2%) compared to countries like Turkey (27.5%) [24], Libya (21%) [13], and the UK (21%) [21]. This necessitates efforts from concerned bodies to enhance the availability of free vaccination against HBV infection for MWH.

This study was conducted in only three hospitals using a nonprobability sampling method at a single point in time. Therefore, selection and recall bias may have been introduced that might hinder the generalizability of the results to all MWH in the study area. Moreover, it was difficult for us to know whether the observed infections occurred before or after employment as MWH, since there was no medical screening at the time of employment. On the other hand, screening of NMWH to control the effect of occupational exposure to hepatitis virus infection may ensure quality in the generated data.

The prevalence of lifetime exposure to HBV infection among MWH was high, while the rate of HCV exposure was low. MWH older than 40 years and those working in hospital laundries were disproportionally infected. Almost two-thirds of MWH did not have protective immunity and were susceptible to HBV infection. Thus, screening upon hire, followed by vaccination of MWH is recommended to reduce the transmission of HBV. Moreover, the need for training in infection prevention is emphasized, particularly in relation to waste handling and disposal.