Uptake of hepatitis B vaccination and its determinants among health care workers in a tertiary health facility in Enugu, South-East, Nigeria

Background Hepatitis B vaccination is the most effective method of prevention for hepatitis B virus infection. It is a major public health problem in Nigeria, and health workers are at increased risk. This study determined the uptake of hepatitis B vaccination and assessed its determinants among health care workers (HCWs). Methods A hospital-based cross-sectional study was conducted between July and August, 2016 using self-administered structured questionnaires among 3132 HCWs in University of Nigeria Teaching Hospital, Enugu, South-East, Nigeria. Data was analysed using SPSS version 22. Binary logistic regression analysis was used to identify factors that influenced uptake of vaccination. Ethical clearance was obtained from the Research Ethics Committee of the health facility. Results The uptake of hepatitis B vaccination was 14.2% (n = 445). The number of doses received were: 3 doses (218/3132, 48.9%), 2 doses (71/3132, 16.0%), and one dose (156/3132, 35.1%). The reasons for non-uptake of vaccination included: cost of vaccine 48 (10.8%), ‘did not believe they could be infected’ 28 (6.6%), long vaccination schedule, and lack of time 150 (35.1%). The Odds for uptake of hepatitis B vaccination were 22% lower among nurses compared to doctors (AOR = 0.78, 95% CI = 0.54–0.98, P = 0.037). It increased with increasing age (AOR = 1.30, 95% CI = 1.08–1.59, P <  0.001), increasing duration of work in the hospital (AOR = 1.19, 95% CI = 1.09–1.32, P = 0.032), and was about twice higher among those that had tertiary education than others that had less education (AOR = 1.96, 95 CI = 0.76–5.07, P = 0.164). Conclusions The uptake of hepatitis B vaccination was low among HCWs in Enugu, Nigeria. Age, staff category, and duration of work in the hospital, were independently associated with hepatitis B vaccination. Provision of adequate hepatitis B surface antigen screening facilities and vaccination sites where the cost of vaccination is subsidized for all HCWs is recommended.


Background
Hepatitis B is spread through contact with blood and body fluids of an infected person. It is a major public health problem in Nigeria and health care workers (HCWs) including general physicians, surgeons, dental surgeons, nurses and other medical staff. These HCWs are at increased risk of acquiring the disease due to occupational exposure to blood and body fluids [1,2]. Hepatitis B is a life-threatening liver infection caused by Hepatitis B Virus (HBV). It can cause chronic and often fatal liver diseases, such as liver cirrhosis and cancer. Globally, about a billion individuals have been infected with HBV at some point in their lifetime and almost 350 million people are chronically infected with HBV, out of which more than a million die annually from its related causes [3]. Majority of the infected cases are living in sub-Saharan Africa [4].
World Health Organization (WHO) reported that about two million health care workers risk occupational exposure to HBV each year and vaccination coverage is low among them [5]. The Department of Health and Human Services, Centers for Disease Control and Prevention (CDC) reported in United States that "the risk of being infected is dependent on the prevalence of the HBV carriers and frequency of exposure of HCWs to blood and body fluids and the infectivity of the virus" [6]. Health care workers in Nigeria are particularly at a greater risk because Nigeria is a holoendemic area, with HBV carrier rate of 15-37% [7]. The risk of acquiring HBV in some cadres of HCWs is four times greater than that of the general population [8].
Hepatitis B vaccination is the mainstay of HBV prevention and has been reported to reduce the risk of acquiring the infection virtually to zero [9,10]. It is recommended for exposed HCWs as part of the universal precautions policy for protection of HCWs [6]. HCWs who are HBV negative after screening should take hepatitis B vaccination, while those who are HBV positive should be treated. However, vaccination among HCWs remains a challenge for many countries [11]. Some studies reported that all HCWs including administrative staff in a hospital can receive the hepatitis B vaccine [11]. The mode of transmission of HBV in health care settings is most often by needle prick injuries and poor adherence to universal precautions [12]. The prevention of occupational hazards requires a thorough knowledge of the risks and practical measures to be taken, and the need for HCWs workers to familiarize themselves with universal work precautions [13]. It is estimated that about a million HCWs had cut and puncture injuries per year [14].
There is wide implementation of policy and uptake of the hepatitis B vaccine in some countries such as UK, USA, and Israel [10]. In 2016, Nigeria developed a national guideline for prevention, care and treatment of HBV and hepatitis C virus (HCV) infections, and vaccination of HCWs was included as one of the preventive methods in health care settings. However, to the best of the authors' knowledge, there is no policy or implementation of any policies that makes uptake of Hepatitis B vaccination compulsory to all HCWs in Nigeria. This study was conducted to evaluate the uptake of hepatitis B vaccination and its determinants among HCWs in a tertiary health facility in South-East, Nigeria.

Study area
This study was conducted between July and August 2016 among HCWs in University of Nigeria Teaching Hospital (UNTH), Enugu, South-East Nigeria. The UNTH is a tertiary health facility, and the national cardiothoracic center of excellence. The facility attends to patients from all over Nigeria.

Study design and sampling technique
This was a hospital-based cross-sectional study. It was conducted prior to the free HBV and HCV screening programmes organised by Roche Products Limited in collaboration with the hospital's Management. To the best of the authors' knowledge, it was the first free HBV and HCV screening programme ever organized for all the hospital's HCWs.

Data collection
Data was collected using pre-tested self-administered structured questionnaires designed to collect information on socio-demographic characteristics, knowledge of transmission and risk factors of HBV, HBV status, uptake of hepatitis B vaccination, doses of vaccine received, and reasons for non-uptake of the vaccine by the participants. Figure 1 shows the respondents' flow chart. The first stage showed that 3132 out of 3422 HCWs completed the questionnaires correctly given a response rate of 91.2%. In the second stage, 893 (28.5%) out of 3132 knew their HBV status. Third stage showed that 872 (97.6%) out of 893 participants that knew their HBV status were HBV negative, while 21 (2.4%) were HBV positive. The fourth stage showed the participants who have received hepatitis B vaccination and the doses received.

Data analysis
Data collected were analysed using SPSS version 22 (SPSS Inc., Chicago, Illinois, USA). Descriptive analyses were expressed as percentages. Socio-demographic characteristics of the respondents (age, sex, marital status, level of education, and duration of work in the hospital) and how it affected the uptake of hepatitis B vaccination was determined. The relationship between the factors and uptake of hepatitis B vaccination was calculated using Chi-square test to determine significance at p < 0.05. Binary logistic regression analysis was performed to determine socio-demographic characteristics of respondents associated with uptake of hepatitis B vaccination and the number of doses received. Variables with statistical significance of P ≤ 0.2 in the bivariate models were included in the multivariate analysis. Strength of association was expressed using Odds ratio and statistical significance presented using P-values and 95% confidence intervals for odds ratio. For all analyses, P-values of < 0.05 were considered statistically significant.

Operational definitions
Uptake of hepatitis B vaccination referred to respondents who have received at least one dose of the hepatitis B vaccine. HBV negative referred to absence of hepatitis B surface antigen (HBsAg), while presence of HBsAg was referred as HBV positive. 'Knew their hepatitis B status' referred to respondents who have been screened in the past and had prior knowledge of their hepatitis B status, whether positive or negative. Full hepatitis B vaccination referred to respondents who have received 3 doses of the vaccine.

Ethical approval
Ethical approval was obtained from Health Research Ethics Committee of the tertiary health facility, and informed written consent was obtained from all the participants.

Socio-demographic characteristics of the participants
The mean age of the participants was 39.4 ± 9.6 (range: 18-75) years. Majority 1151(36.7%) were in the 31-40 years age group. About three quarters 2237 (71.4%) had tertiary education, 2174 (69.4%) were married and 580 (18.5%) were nurses. Majority of the participants 1938 (61.9%) had worked for more than 5 years (Table 1). Table 2 shows that less than half of the participants knew that hepatitis B could be transmitted by needle prick, sharing of sharp objects, and sexual intercourse, while about 70% knew that blood transfusion was a mode of transmission. Only 3% believed it could be transmitted by shaking of hands and 16.3% did not know any mode of transmission. Table 3 shows the participants in each stage of the study. A total of 297 (9.5%) doctors, 716 (22.9%) nurses/pharmacists/lab workers, and 2119 (67.7%) administrative staff were involved in the study. Participants who knew their HBsAg status were 893 (28.5%). Twenty one, 21 (2.4%) were HBsAg positive, while 872 (97.6%) were HBsAg negative. Among the 872 participants who were HBsAg negative, 445 (51.0%) have received at least one dose of hepatitis B vaccine while 427 (49.0%) have not received any dose of hepatitis B vaccine.

Reasons for non-uptake of hepatitis B vaccine by the participants
The reasons for non-uptake of hepatitis B vaccination by the 427 HBsAg negative participants included: cost of  Table 4.
Factors associated with uptake of hepatitis B vaccination among participants that were hepatitis B negative Table 5 shows factors associated with uptake of hepatitis B vaccination by the participants. After adjusting for age, sex, marital status, level of education, and professional categories, the Odds for uptake of hepatitis B vaccination were higher among single/separated/widowed participants compared to those that were married (AOR = 1.38, 95% CI = 1.01-1.92, P = 0.050). The Odds for uptake of hepatitis B vaccination were 22% lower among nurses compared to doctors (AOR = 0.78, 95% CI = 0.54-0.98, P = 0.037), while the Odds for the uptake of hepatitis B vaccination increased with increasing age (AOR = 1.30, 95% CI = 1.08-1.59, P < 0.001). The Odds for uptake of hepatitis B vaccination also increased with increasing duration of work in the hospital (AOR = 1.19, 95% CI = 1.09-1.32, P = 0.032). It was about 2.1 higher among participants who had secondary education compared with those that had primary education (AOR = 2.06, 95% CI = 0.75-5.61, P = 0.159), and about twice higher among those that had tertiary education than others that had less education (AOR = 1.96, 95 CI = 0.76-5.07, P = 0.164).

Discussion
This study showed that the uptake of hepatitis B vaccination among HCWs in Enugu, Nigeria was poor. This is similar to the study conducted in Pakistan [15], but differs from other studies from India and Ethiopia [16,17]. The authors found that 28.5% of the participants knew their hepatitis B status, and that 2.4% were hepatitis B positive, while 97.6% were hepatitis B negative. The observed low knowledge of hepatitis B status (28.5%) in this study could be due to absence of pre-employment screening for hepatitis B as well as lack of policy concerning hepatitis B screening in the facility. It also  [18,19]. However, it is lower than 22.4% reported in the similar study in 2006 [20], and also among HCWs in a teaching hospital in Ile-Ife, South-West Nigeria which revealed that 65% of the health workers have been vaccinated against hepatitis B virus [4]. The observed uptake in this study is also lower than 54.8% reported among theatre and laboratory workers at a teaching hospital in Imo state, Nigeria [21].
These differences could be due to the fact that the current study involved a larger population, and also administrative staff which were not involved in previous studies. This study also revealed that only 28.5% of the participants had prior knowledge of their hepatitis B status. This poor result could be due to the cost of screening for hepatitis B surface antigen and its poor accessibility in Nigeria. Regular free or subsidized screening programmes might bring improvement in this regard.
It was observed that a higher proportion of administrative staff have not received hepatitis B vaccination compared to nurses, doctors, pharmacists and laboratory technologists. This higher uptake of hepatitis B vaccination among the clinical than administrative staff could be as a result of their pre-employment training and education which might have included the importance and safety of vaccination to health. The management of health facilities should pay attention to administrative cadre of staff for improved uptake of hepatitis B vaccination among its HCWs. Similarly, the duration of HCWs that had worked in the facility also influenced the uptake of hepatitis B vaccination. Higher proportion of those who had worked for more than 5 years in the facility received hepatitis B vaccination than those who had worked for less. This result could be due to lack of policy concerning hepatitis B vaccination of workers in the hospital. Also higher proportion of participants older than 30 years of age received hepatitis B vaccination than those below 30 years old. This higher uptake of hepatitis B vaccination among older HCWs who are also more likely to have worked for longer  duration might be due to their previous observations. It is possible they might have observed their colleagues suffer fulminant hepatitis and/or liver cancer as a result of possible non-uptake of hepatitis B vaccination. The reason for this higher uptake among this category of HCWs may also be due to previous hepatitis B vaccination related encouragements from colleagues. Such encouragement could lead to increase in awareness and knowledge of importance of screening and uptake of hepatitis B vaccination for those who are hepatitis B negative, and treatment for those who are hepatitis B positive. Formulation of policies to make screening for hepatitis B surface antigen and uptake of hepatitis B vaccination compulsory and at free or subsidized cost for all HCWs may bring improvement in uptake of hepatitis B vaccine. This study found that 48.9% of those who were vaccinated had full coverage of the three doses of the vaccine, while 16 and 35.1% took two or one dose respectively. This is similar to the study conducted in Tanzania, and India among HCWs where 48.8 and 50% received three doses of the vaccine respectively [22,23]. It is also similar to the study conducted among doctors and nurses in Lagos, Nigeria where 48.5% completed three doses of hepatitis B vaccination [24]. It is however lower than results documented in the study conducted among doctors and nurses in Iran which reported that 86.2% completed the recommended three doses of vaccine [25]. This difference might be due to the fact that the present study involved all health workers including administrative staff compared to study from Iran where only doctors and nurses were included. Thus, the differences in this study compared with other studies could be due to the inclusion of administrative staff, and the larger sample size. Interestingly, those who received three doses of vaccine in the current study is higher than the findings in other studies conducted in Nigeria, Sweden, Pakistan, and South Africa which reported 16.3, 29.7, 39.8, 37.2, and 19.9% respectively [20,21,[26][27][28]. However, it is lower  [17].
Our study revealed that age, staff category and duration of work in the facility significantly influenced uptake of hepatitis B vaccination, but no factor significantly influenced full vaccination status. However, after adjusting for confounders, the odds for full hepatitis B vaccination were higher among female participants than males (AOR = 1.17, 95%CI = 0.76-1.78, P = 0.265), tertiary education compared to primary education (AOR = 2.94, 95% CI = 0.64-12.43, P = 0.328), and among participants with longer duration of work (AOR = 1.23, 95%CI = 0.96-1.59, P = 0.106). These observations are similar to findings from some other studies which reported that sex, years of occupational practice, and educational status significantly influenced vaccination pattern [4,20,21].
The findings in the current study showed that 10.8% of the participants did not receive hepatitis B vaccination because of cost of vaccination, 47.5% did not know where to take the vaccination, 6.6% believed they could not be infected, while 51.1% gave other reasons such as long vaccination schedule, and lack of time. These findings are similar to a study conducted to find reasons for non-uptake of vaccine which reported inadequate vaccine information as a factor [11] and unavailability of vaccine and high cost of vaccine as major determinants [29]. The prevalence of HBV markers which includes individuals with HBsAg, anti-HBc, and anti-HBs who do not need hepatitis B vaccination is 72.5% in Nigeria [30]. Recommendations from American College of Physicians and the Centers for Disease Control and Prevention is that screening for HBV should include testing to three HBV screening sero-markers so that persons can be classified into the appropriate hepatitis B category and properly recommended to receive vaccination, counselling, and linkage to care and treatment [31]. However in Nigeria, accessibility and cost of hepatitis B serological tests for HBV markers is a great challenge. The authors' opinion is that all HCWs should be screened for only HBsAg, and those that are negative should receive hepatitis B vaccination to reduce the cost and other challenges.

Conclusions
This study revealed that uptake of hepatitis B vaccination as well as number of doses received was low among HCWs in Enugu, Nigeria. Age, staff category, and duration of work in the hospital, were independently associated with hepatitis B vaccination. It is therefore recommended that Management of health facilities in Nigeria should provide hepatitis B surface antigen screening facilities and hepatitis B vaccination sites for easy accessibility, and also subsidize the cost of screening for hepatitis B surface antigen and hepatitis B vaccination for all HCWs. They should also formulate policies that make screening for hepatitis B surface antigen and uptake of hepatitis B vaccination for hepatitis B negative HCWs compulsory and at free or subsidized cost. If possible, the Management should also frequently organize free screening for HBV for all its HCWs. This would increase the proportion of HCWs that know their hepatitis B status, as well as stimulate those that are hepatitis B negative and positive to receive the required vaccination and treatment respectively.