Hepatitis B virus infection and its associated factors among medical waste collectors at public health facilities in eastern Ethiopia: a facility-based cross-sectional study

A facility-based cross-sectional study was conducted in public health facilities of Harari region, Diredawa administration, and east and west Hararghe zones of Oromia regional state, eastern Ethiopia, from March to June 2018. According to the data obtained from the respective health offices, there were around 211 public health facilities (11 hospitals and 200 health centers) in the study area (115 health centers and 5 hospitals are found in east Hararghe, 65 health centers and 2 hospitals in west Hararghe, 12 health centers and 2 hospitals in Diredawa, and 8 health centers and 2 hospitals in Harar) (Fig. 1).

Multistage sampling technique was used and facilities were then stratified into hospitals and health centers. Eleven Hospitals and 30 health centers were selected from a total of 211 health facilities in eastern Ethiopia by lottery method. Sample size was determined using single population proportion formula for both objectives. Accordingly, sample size was calculated considering a beta of 80% and an alpha of 0.05% and design effect of 1.5. It was estimated 267 samples were needed which was obtained with the second objective (risk factors for HBV infection) from previous study by Anagaw et al. [12]. The Study participants were then proportionally allocated for respective selected health institutions based on the number of study population working at each selected health institution. Registered lists of study participants were used as sampling frame.

All medical waste collectors who were working at health facilities and healthy enough to provide information were included. Those medical waste collectors who were critically ill, have mental problem and have not engaged/exposed to medical waste management were excluded.

The primary outcome of this study was prevalence of HBV infection and our secondary outcome were factors associated with HBV infections such as socio demographic characteristics, occupational exposure to medical waste, immunization with hepatitis B virus vaccines, blood transfusions, multiple sexual partners, and family history of liver disease and others non-occupational risk factors.

A pretested structured questionnaire was used for data collection from medical waste collectors. Five Nurses and five Public health professionals were recruited to facilitate data collection. The questionnaire was developed after reviewing different literature and pretested on 5% of sample size working at hospital which were not included in the study [11, 12, 21, 22]. The questionnaire was translated to local language (Afan Oromo and Amharic). During data collection, the data was checked for its completeness each day by supervisors and investigators after it was collected. For blood sample collection, all material we used were tested before purchase. Blood sample was collected with standard precaution and centrifuged to separate serum from whole blood immediately after collection of blood.

Five laboratory professionals were recruited to collect blood sample. 2.5 ml of venous blood samples was collected in tubes aseptically after written consents was obtained from study subjects. Serum was separated by centrifugation at 3000 r/min for 5 min after the blood was clotted. The blood samples were labeled with unique identification numbers. The serum was separated by centrifugation and was placed into Eppendorf tubes. The serological tests were performed using hepatitis B surface antigen rapid test kits by Wondfo one step HBsAg test strip according to the manufacturer’s manual (Guangzhou Wondfo Biotech Co., Ltd. (Wondfo)). This test strip has sensitivity and specificity of 96.2 and 99.3% respectively [23].

Collected data was entered into Epi-data Version 3.1 and exported to SPSS version 22 statistical packages for analysis. Descriptive summary measures were made using frequency table, percentage and mean and standard deviation. Chi-square and Fisher exact tests were used to assess risk of association.

The variables with a p-value of less than 0.2 in the bivariate analysis were included in the multivariable analysis. Multivariable logistic regression (adjusted odds ratio with 95% confidence interval) analysis was employed to identify independent variables associated with HBV infections adjusting for other variables. Model fitness was checked using Hosmer Lemeshow goodness of fit and variables with P-value < 0.05 at 95% CI was declared statistical significance.

A total of 260 (97.38%) medical waste collectors have participated in this study. Seven participants refused to participate in this study. Two hundred thirty-seven (91.2%) participants were females (Table 1). The median age of the study participant was 29 years (IQR = 8). The majority (58.1%) of the study participants were married whereas the median years of service was 4 years (IQR = 4) (Table 1).

According to this study, 20.4% [95% CI; 15.8, 25.6] of the respondents are found positive for HBsAg test. There was no statistically significant difference in the rate of HBV infection between socio-demographic characteristics of the study participants (P > 0.05). Of note, statistically significant difference was noted in exposure to blood ungloved (P = 0.002), history of multiple sexual partner (P = 0.001), and being unvaccinated for HBV (P = 0.001).

According to this study, 51.9% (135) of the study participants have poor knowledge on universal precaution guideline and only 39.6% (103) have participated in training program about infection prevention or universal precaution. More than two third (76.9%) said they cleaned their hand after touching or collection of blood or other body fluids. Two hundred two (85.4%) study subjects said they wear glove consistently for personal protective purpose. On the other hand, about one half, 43.1% of the study participants have history of exposure to any types of body fluids like waste contaminated by body fluids (blood, peritoneal, pericardial, pleural, synovial, CSF amniotic fluids and others). Out of these study participants, 61.61% have history of exposure to blood ungloved. The majority 52.69% (137) of the study participants said they have recapped needle that were in appropriately recapped. About 41.2% (107) of study participants said they had history of sharp material injury, and 38.5% (100) had history of needle stick injury. Fourth eight (44.86%) of the study participants had had sharp injury twice (Table 2). There was no significant difference in HBsAg positivity with respect to frequency of sharp injury (p value > 0.05).

Thirty-five (13.5%) study subjects said they had history of surgical operation. Approximately 9% (23) of the study participants had participated in blood transfusion. Furthermore, 11.5% (30) of the study participants said they have been diagnosed with jaundice and/or liver diseases, and 12.3% (32), and 22.7% (59), had history of tattooing and tooth extraction respectively. From the total study subjects, 8.1% (21) said that they had history of multiple sexual partners in the last 1 year out of which 3.8% (10) had sex with commercial sex workers. Eleven study subjects (4.1%) said that they had family history of chronic liver disease. Among the total study subjects, 51.2% (133) said that they have been vaccinated for HBV.

Study subjects who have never been vaccinated for HBV were 6.35 (AOR = 6.35; 95%CI: [2.53–15.96]) times more likely to be positive for HBsAg compared to those who have been vaccinated for HBV (Table 3). Medical waste collectors who had history of blood transfusion (received) and tattooing were 3.54 and 2.86 times (AOR; 3.54; 95%CI, [1.02–12.24]; AOR = 2.86; 95% CI: [1.12–7.27]) more likely to be positive for HBsAg than their counterparts respectively (Table 3). Furthermore, the odds of being positive for HBV infection is 10.28 (AOR = 10.28; 95%CI: [4.16–25.38]) times higher among medical waste collectors who had multiple sexual partners in the last 1 years than those who had no history of multiple sexual partners.

This study is a large-scale study including many health facilities and geographic areas which may increase its representativeness of the finding. However, we recognized certain limitations including insufficient immunoassay logistics supply which restricted this study to provide data on other HBV serological markers as HBeAg, IgM and IgG anti-HBc”. In addition, the use of rapid tests in the absence of confirmatory conventional immunoassays may be also a limitation. This limited the study classifying whether infections are acute or chronic and whether the degree of infectivity correlates with a high level of HBV replication or not.