Credit: BMC Infectious Diseases
Hepatitis B virus (HBV) infection is a major threat to public health globally. According to the World Health Organization (WHO), approximately 257 million people are infected with chronic HBV. Infection with HBV can increase the risk of death from liver cirrhosis and hepatocellular carcinoma, which is the sixth most common cancer and the third cause of cancer death worldwide. The WHO reported that hepatitis B prevalence is the highest in the western Pacific region and Africa, where 6.2 and 6.1% of the adult population are infected, respectively. Sierra Leone, located in West Africa, is considered a high-endemic area. A study conducted among primary school children, in 1998, detected HBsAg in 18% of the children tested. In 2005, a study showed a 6.2% seroprevalence of hepatitis B among pregnant women of middle and high socio-economic class in Sierra Leone. Recently, a study screening blood donor candidates for blood-borne pathogens found aHBsAg prevalence of 15% in men and 13% in women from a single hospital in Tonkolili Province, Sierra Leone. These results illustrate the serious public health risks that hepatitis B poses in Sierra Leone. In addition, HBV continues to be an understudied topic in Sierra Leone. Due to limited resources, little has been done to combat hepatitis B in Sierra Leone despite the suspected high burden of disease. Although the hepatitis B vaccine was introduced for 6 to 14 week-old children, there are currently no active programs administering the vaccine at birth. Furthermore no coordinated HBV vaccination program been put in place to prevent infection among the adult population.
Healthcare workers (HCWs) are considered a high-risk group for HBV infection due to occupational exposure to blood-borne pathogens. Previous studies in Africa found high HBV infection and exposure rates (roughly 10%) in HCWs in South Africa and Nigeria. Worldwide, approximately 2 million HCWs are infected with HBV through sharp injury. This study was designed to evaluate the prevalence of HBV markers in HCWs as well as to assess their knowledge of HBV infection and prevention in Sierra Leone.
Methods
Study area and sample population
A cross-sectional study was conducted at the No. 34 Military Hospital in Freetown, Sierra Leone from March 20 to April 10, 2017. This hospital serves as a medical center for the Republic of Sierra Leone Armed Forces in addition to also being a teaching and general hospital. A total of HCWs, including medical doctors, nurses and other non-clinical health workers, were studied and written, informed consent was obtained from each subject.
Laboratory detection of hepatitis B virus
Blood samples were drawn from the antecubital vein of the 211 participants by phlebotomists of the No. 34 Military Hospital clinical laboratory then centrifuged for 5 min at 12,000 g at room temperature. Serological tests were performed to detect five markers including HBsAg, anti-HBs, HBeAg, anti-HBe and anti-HBc, by using a one-step rapid immunochromatographic test (Shanghai Kehua Bio-engineering Co., Ltd., Shanghai, China). Test results were interpreted and reported as positive or negative based on the manufacturer’s instructions.
Viral deoxyribonucleic acid (DNA) was extracted using the QIAamp DNA Blood Mini Kit (QIAGEN, Germantown, MD, USA) according to the manufacturer’s instructions. HBV DNA was amplified using real-time PCR (qPCR) (Light Cycler Software Version 4.1, Roche Diagnostics, Penzburg, Germany) HBV DNA assay kits (Sansure Biotech, Changsha, China) in all HBsAg positive samples.
Design and administration of the questionnaire
Data were collected using a self-administered questionnaire, which was developed after reviewing relevant research. The survey had questions on socio-demographic characteristics, knowledge of HBV clinical outcome, route of transmission and preventive measures against hepatitis B infection, previous infection, and previous vaccination history. No vaccinations were offered to HCWs as part of this study. Seventeen questions had binary (yes or no) responses, and three multi-items questions focusing on the clinical outcome of HBV infection, route of transmission and proper preventive measures had only one correct answer. Each study participant was expected to complete the questionnaire.
Statistical analysis
The data obtained from the questionnaire and the results of the laboratory test were analyzed using SPSS (version 17.0, SPSS Inc. Chicago, IL). The response for each question was given a score of one and zero indicating a right or wrong answer was provided, respectively. Then we summed and graded the total scores as ‘poor’, ‘intermediate’ or ‘adequate’ level for each study participant based on the distribution located in the tri-sectional quantiles of the grouped data array. The Pearson Chi-square test was used to determine the relationships between participant characteristics and HBV marker detection rates. Multivariable factor analysis for current HBV infection was carried out for seven possible risk factors, including age, gender, working experience years, education background, occupation, vaccination, and sharp injury history. Differences were considered statistically significant when the p value was < 0.05.
Results
Demographic characteristics among HCWs
The median age of the 211 HCWs who participated in the study was 39.0 years (range:18–59). Roughly half of participants were male (51.2%), over the age of 39 (46.9%), and had spent less than 9 years in their current job (46.4%). The majority of HCWs had a middle education level (Diploma Certificate, 78.7%) (Table 1).
Prevalence of HBV
Of the 211 HCWs, the positive detection rates of the five markers HBsAg, anti-HBs, HBeAg, anti-HBe and anti-HBc were 10.0, 4.7, 0.5, 10.9 and 13.3%, respectively (Table 1). Twenty-one of the (10.0%) HCWs tested positive for current HBV infections (HBsAg positive, anti-HBc positive) (Table 2), nine (4.3%) were considered immune due to past infection (HBsAg negative and anti-HBc positive; anti-HBs positive), and nine (4.3%) participants were immune due to hepatitis B vaccination (only anti-HBs positive). In total, 172 (81.5%) participants were considered susceptible (all markers negative) (Table 2). Among 21 participants who were HBsAg positive, 13 (61.9%) were HBV DNA positive. Twelve of them were determined very low-level HBV DNA (< 10^3) and one had a DNA concentration of 5.6 × 10^3 copies/mL.
Anti-HBs positive rate of participants who reported receiving a HB vaccine significantly increased. This was in comparison to participants who had not received vaccination (16.2% vs. 1.7%, p = 0.001) (Table 2). Of the 211 participants, only 14 (6.6%) participants had clear HBV infection history, out of which 4 tested positive for serological markers (Table 2). The prevalence of the “current infection” group was significantly higher in HCWs < 39 years old (p = 0.018) (Table 3). Multivariable factor analysis for risk for current HBV infection showed that there was a significantly lower risk for current HBV infection among those HCWs aged > 39 years (OR = 0.337; 95% CI:0.116–0.980; p = 0.046) (Table 4).
Knowledge of HBV infection and associated factors
According to participants’ responses, 77.3% (163/211) of staff were not aware of clinical outcomes of HBV infection, while 63 (29.9%) and 93(44.1%) had a poor knowledge on transmission routes and preventive measures of HBV, respectively. The survey also revealed that working experience was associated with greater knowledge of preventive measures for HBV(p = 0.017) and medical doctors were more knowledgeable about the consequences of HBV infection (p = 0.05) (Table 5).
Conclusions
HCWs in Sierra Leone lacked adequate knowledge of the hepatitis B virus.. Additionally, there were low coverage rates of hepatitis B vaccination that does not seem to be able to meet the WHO recommendations, leaving many HCWs susceptible to hepatitis B infection in the sampled population. Local health authorities need to make a coordinated effort to increase vaccination uptake considering the cost-effectiveness of broad immunization against hepatitis B and incorporate more intensive training against blood-borne pathogens for HCWs in Sierra Leone.
