Seroprevalence of Hepatitis B Virus Infection and Risk Factors among Adolescents and Youth in Secondary School in 2018, Commune of Covè, Benin

Background: Hepatitis B is a vaccine-preventable liver infection caused by the hepatitis B virus. The study aimed to determine the prevalence and associated factors of hepatitis B infection in adolescents and youth attending secondary school in Cove, urban area in Benin. Methods: From 4th to 10th February 2018, a cross-sectional survey was conducted among adolescents and youth aged 15 to 24 years old. Subjects were randomly selected. Hepatitis B surface antigenaemia (HBsAg) was assayed in blood using rapid enzyme-linked immunosorbent assay kits. Univariate and multivariate analyses were performed. Results: Two hundred adolescents and youth were recruited. The seroprevalence of hepatitis B virus infection was 18.50%. According to the multivariate logistic regression model, being infected by hepatitis B was 4.32 times higher in the age group of 15 - 19 years old than in 20 - 24 years age group (PR = 4.32 95% CI [1.51 - 12.34], p = 0.0063). Similarly, students who had not been aware of hepatitis B were more infected than those who were sensitized (PR = 14.60 [95% CI 4.98 - 4.27], p = 0.0001). With regard to lifestyle, individuals with tattoos or piercings were 8.60 times more likely to have been infected by HBV than those without tattoos or piercings, (PR = 8.60; 95% CI [3.41 - 21.70], p < 0.0001). Conclusion: The seroprevalence of hepatitis B among adolescents and youth attending secondary school was high. Regular screening of HVB infection status should be included in school health services in Benin. Awareness campaigns and health education on HVB transmission and prevention should be promoted and strengthened.


Introduction
Viral Hepatitis B infection (HBV) is a major global health problem and is an important cause of death worldwide [1] [2] [3]. Hepatitis B is spread when blood, semen, or other body fluids from a person infected with the virus enter the body of someone who is not infected [4]. The virus is most commonly transmitted from mother to child during birth and delivery, as well as through contact with blood or other body fluids, including sex with an infected partner, injection-drug use that involves sharing needles, syringes, or drug-preparation equipment and needle sticks or exposures to sharp instruments [1] [4]. Complications of chronic HBV infection such as chronic hepatitis, cirrhosis, and hepatocellular carcinoma [5] account for 500,000 to 1.4 million deaths yearly [3] [6].
In Sub-Saharan Africa, several studies estimated between 10% and 15% seroprevalence of HBV surface antigen (HBsAg) [7]. As of 2016, only 27 million people (10.5% of all people estimated to be living with hepatitis B) were aware of their infection [8].
In Benin, the prevalence of HBV infection, cirrhosis and primary liver cancer are poorly documented in adolescents and youth but clinical reports are alarming. The prevalence of HBV is estimated from the 2013 national survey to be 9.9%, which corresponds to about 1,000,000 people with HBV in Benin's estimated population of 10 million [9]. In 2019, seroprevalence of HBV and its associated factors were determined based on data from a screening campaign targeting the general volunteers in Benin. HBV seroprevalence was 6% and male subjects elder than 17 years old with secondary-level education were mainly affected [10]. Age, gender, geographic region, socioeconomic status, immunization status, lifestyle, sanitation and hygiene, and their relative contributions can influence the prevalence of HBV infection [11] [12]. Among the interventions carried out by Benin country, there were: 1) the introduction in 2002 of the hepatitis B vaccine, systematic and free of charge for children from 0 to 11 months of age within the framework of the Expanded Programme on Immunisation (EPI) [9], and the 2) the promulgation of law 2017-28 on the prevention, management and control of hepatitis B and C in the Republic of Benin adopted on September 14, 2017 [13]. Unfortunately, most people with chronic viral hepatitis are not aware of their status and do not receive appropriate treatment, particularly young people aged 15 to 24 [10] [12] [14]. Very recently, from October 1, 2020, the vaccine against HBV is administered within 24 hours after birth. The majority of them were not vaccinated because they were born before the beginning of EPI intervention. The objectives of our study were therefore to determine the prevalence of HBV infection among adolescents and youth, and iden-deviate (1.96 for 95% confidence level) and i = 0.05 is the desired precision or sampling error (tolerance error 5%). The prevalence p of HBV considered was 9.9% (from the Ministry of Health's 2013 statistics book) [17] and q is the proportion of the population that does not have the characteristic (q = 1 − p). The required minimum sample size was n = 139 adolescents and youth.

Data Collection Procedure
Demographic and explanatory variables were collected using a structured questionnaire via face-to-face interview. The questionnaire was pretested and validated 1 two weeks before the beginning of the work and the contents found not to be ambiguous to the subjects. The questionnaire was sectionalised into socio-demographic characteristics, risk factors associated with HBV infection and vaccination history. Micropoint® rapid diagnostic tests (RDTs) were used for HBsAg detection. HBsAg-positive corresponded to the presence of HBsAg in serum and indicates that the individual has a current infection. The sensitivity and specificity of the RDT were 97.8% and 99.0% respectively and the storage temperature was 2˚C -30˚C. Three trained interviewers were responsible for completing the questionnaires and the laboratory technicians were trained for taking blood samples and for testing by using RDT. Supervision was provided by HBV midwife specialist. The laboratory test results for participants were anonymously linked to their questionnaire information through unique identifiers.

Study Variables
The dependent variable is the presence or absence of HBV infection in the adolescent and youth. The independent variables were: 1) Socio-demographic variables of adolescents and youth attending school (age, sex, school level, school attended); 2) Socio-demographic variables of the parents of adolescents and youth (size of household; father's occupation; mother's occupation; father's education level); 3) Variables related to the knowledge (knowledge on hepatitis); 4) Variables related to the lifestyle or personal history (presence of tattoos and/or piercings; alcohol consumption; drug consumption; use of personal cutlery; circumcision/excision; history of blood transfusion; history of surgery; history of intravenous injection; use of personal sharp objects); 5) Sex life variables (sexual activity; multi-partnership; history of sexually transmitted infections; having unprotected sex; casual sex; anal sex; oral sex; group sex).

Data Processing and Analysis
Data analysis was carried out using EPI-INFO version 7.0 software. First, a descriptive analysis of the socio-demographic variables was carried out. In a second step, we tested the association between HBV infection and the independent variables with the Chi2 test. In the case where the theoretical numbers are less than 5 the Fisher test was considered. In the multivariate model, the association is considered significant at the p < 0.05 level. The strength of the association between HBV and the explanatory variables was expressed using prevalence ratios (PR). In the subsample of sexually active young people, we focused on the

Ethical Considerations
The administrative and health authorities were informed and they gave a research permit. Data collection was preceded by free, informed and consent. Before the beginning of the data collection, the enumerators visited the selected schools to familiarize themselves with the school authorities and students. During the familiarization visits, the students and teachers were given a brief talk on HBV infection and the objectives of the study were explained to the students. The selected students were given a consent form to take home to their parents and brought back the next day. The data collected were strictly confidential and anonymous. Before the survey began, a working session was held with health facility managers of the study area on the management of positive HBsAg. Reference forms were designed for this purpose and gave to the HBsAg positive participants. They were sent to the medical team for free additional exams and treatments according to the national policy.

Prevalence of Viral Hepatitis B
The prevalence of HBV was 18.50% among adolescents and youth attending secondary school in the commune of Covè.

Socio-Demographic Characteristics of Adolescents and Youth
A total of 200 adolescents and youth were included in our study, 33 in three colleges and 34 in two colleges. The average age of sampling students was 18.11 ± 2 years. The most represented age group was 15 to 19 years (77.50%). Males represented 52.00% of the population sampled. The majority of the respondents were in the first level of secondary school (79.00%).

Socio-Demographic Characteristics of the Parents of Adolescents and Youth
A total of 27.5% of the fathers of the respondents had never attended school. The majority of fathers were farmers (50.50%), and artisans (21.00%). Their mothers were mostly shopkeepers (53.00%), and housewives (26.00%) ( Table 1).

Knowledge of Viral Hepatitis B
More than half (51%) of the respondents had never heard of hepatitis. Of those who had heard about it, 46.0% had heard about it in a health centre, 17.5% on the radio, 15.5% on the internet, 9.0% from their parents, 7.0% from television, and 5.5% from newspapers.

Lifestyle/Medical History
The proportion of students who declared that they have used personal sharp objects was 73.5%. 33.5% said they had misused at least once and 2.5% said that  20.5% had a tattoo or piercing. Also 18% and 4.5% respectively benefit from blood transfusions and surgical interventions at least once. All the males in the sample (n = 104) had been circumcised and only one of the girls (n = 96) in our survey had been circumcised. The majority of students received an intravenous injection at least once (75.5%).

Sexual Behaviour
A large proportion of students were sexually active (61.00%). The proportion of them who had an STI at least once was 10%, and only gonococcal and vaginal candidiasis infection was cited.
Among the 122 sexually active individuals, 31.10% declared to have had their first sexual intercourse between 10 and 15 years old and 68.85% between 16 and 24 years old.
In the group of sexually active subjects, 20.5% had more than one sexual Some of the students practised anal sex, oral sex and group sex: 4.09%, 24.6% and 0.9% respectively ( Table 2).

Vaccination
Only six individuals had been vaccinated against HBV infection. Of those, three of them received a single dose, two of them received two doses and one received three doses.

Association between Viral Hepatitis B Infection and Socio-Demographic Characteristics of Adolescents and Youth Attending School, Univariate Analysis
In the univariate analysis, only age variable was significantly linked to HBV infection prevalence. The proportion of infection was 1.87 times higher in 15 -19 years old than in 20 -24 years old (RP = 1.87; 95% CI [1.03 -3.35] and p = 0.0400) ( Table 3).
In univariate analysis, parental socio-demographic characteristics were not associated with HBV infection in adolescents and youth.

Association between Viral Hepatitis B Infection and the Level of Knowledge, Univariate Analysis
The level of knowledge was significantly associated with the prevalence of HBV infection (p-value = 0.0002). Individuals who had received no information about HBV were 3.48 times more likely to be infected with HBV than those who had received information (PR = 3.48; 95% CI [1.67 -7.24]) ( Table 4).

Association between Hepatitis B Infection and Lifestyle of
Adolescents and Young People, Univariate Analysis Adolescents or youth who had tattoos and/or piercings had a four times higher prevalence of hepatitis B compared to those without tattoos or piercings (p < 0.0001 and PR = 4.09; 95% CI [2.37 -7.06]). Adolescents or youth with a history of blood transfusion had a two times higher proportion of being infected compared to those without blood transfusions p = 0.0410 (Table 4).

Association between Viral Hepatitis B Infection and Sexual
Behaviour, Univariate Analysis In the target group of sexually active students (61.00% of the sample), individuals who had their first sexual intercourse between 10 and 15 years old were 3.43 times more likely to have HBV infection than those who had their first sexual intercourse between 16 and 24 years old (p = 0.0006, RP = 3.43; 95% CI [1.63 -7.24]).
Similarly, individuals who had no sexual partner during 12 months prior to the study were 8.70 times less likely to have HBV infection than individuals who had more than one partner during this period (p = 0.0100 and PR = 8.70; 95% CI [1.67 -45.44]).
Protection during sexual intercourse was also related to HBV infection (p = 0.0020 and PR = 6.00, 95% CI [1.47 -24.88]). Individuals who did not use a condom during sex were 6 times more likely to have HBV infection than those who used protection.
Finally, those who had group sex were 5.5 times more likely to have hepatitis B than those who did not (PR = 5.50; 95% CI [3.76 -8.02]) and p = 0.0300 (Table 5). Open Journal of Epidemiology     Table 3 and Table 4).

Discussion
The study aimed to determine the prevalence of HBV infection and associated factors in the adolescent and youth attending school in the commune of Covè.
The seroprevalence of HBV was high at 18.5%. The factors significantly associated with HBV were age, level of knowledge and the presence of tattoos or piercings. In the subgroup of sexually active adolescents and youth, age at first sexual intercourse, number of partners, having unprotected sex, casual sex and group sex were significantly associated with the prevalence of HBV infection.

Prevalence of Viral Hepatitis B Infection in Adolescents and Youth
None of the participants who were tested positive for HBV infection were aware of their status. This is a concern and raises the issue of low screening for HBV infection in the adolescent and youth in Benin. This high rate may be explained by the fact that most of the young people included in the survey were born before the introduction of the HBV vaccine on the EPI intervention, or did not have access to this vaccination due to lack of information or parental neglect. Similar results were found in Côte d'Ivoire in 2013, the prevalence of HBsAg was estimated between 14% and 15% in the age group of 12 -28 years old [18].
Although HBV control strategies are comparable in Nigeria [e.g. introduction of HBV vaccination in the EPI program in 2004), the prevalence of disease was lower among young people in Enugu (3.1%) according to Eke study's in 2015 [19].

Factors Associated with Viral Hepatitis B Virus Infection
In this study, we had no information on the serological status of mothers, but in Benin, since 2002, HBV vaccine has been administered to infants from 6 weeks of age [9] as part of EPI intervention and therefore probably the majority of the students included in the study were not vaccinated in childhood and neither were their parents. The risk of mother-child contamination is therefore not negligible.

Age and Level of Knowledge
Age was significantly linked to the prevalence of HBV infection. HBV infection was 4.32 times higher in 15 -19 years old than in 20 -24 years old. In addition, we found that for 1/3 of the respondents, the first sexual intercourse occurred before the age of 16 years old and this was associated with a high proportion of HBV infection. A contrarily, a study conducted among children and adolescents (0 -18 years old) in Nigeria showed that positivity of HBsAg was not linked to age group even if high prevalence was observed among older age group [20].
This high prevalence was probably due to the lack of experience and the lack of awareness among the youngest students regarding their lifestyle and sexual behaviour (e.g. having unprotected sex) [21]. These results mean that the pre and early adolescence age are the best age to focus on to prevent HBV by increasing knowledge and awareness to HBV and changing beliefs/attitudes and cultural norms that facilitate transmission of the disease [20].
48% of the students declared that they have heard about HBV infection. This contrasts with a lower actual knowledge on HBV mode of transmission and prevention, indicating a superficial and insufficient knowledge of the disease.
The proportion of students aware of HBV in the current study was lower than in the Thaver's et al., [22]  We found that vaccination declaration was not related to HBV infection, probably because of the small number of students who received the vaccine.
Nevertheless, there is evidence that the HBV vaccine is key to the prevention of this disease [14] [23]. The WHO recommends that all infants should receive the vaccine as soon as possible after birth, and preferably within 24 hours. The adolescents and youth should be vaccinated to by free.
All adolescents and youth attending school or not should be vaccinated through a free vaccination programme.

History of Tattoos and Piercings
Having tattoos and piercings was a major risk factor for HBV. The same results were found by Eke [19] and colleagues among Nigerian adolescents. In addition to tattoos and piercings, circumcision and surgical history were also found as

Limitation of the Study
Biases related to cross-sectional and questionnaire studies must be considered for this study. In addition, only the results of RDT were taken into account in this work. The HBV status of the parents of the participants was unknown.

Conclusions
The prevalence of HBV among adolescents and youth attending school in the commune of Covè was very high. The risk factors identified were: age, knowledge of adolescents and youth, having tattoos and piercings, age at first sexual intercourse, multiple sexual partnerships, occasional sex and group sex.
There is an urgent need to strengthen prevention strategies against HBV in Benin, in particular universal vaccination and targeted behaviour change communication to adolescents and youth.

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