A single center cross-sectional study was conducted in July-December 2021 at Tikur Anbessa specialized hospital (TASH), the main tertiary referral center in Addis Ababa, Ethiopia. TASH gastroenterology and hepatology unit runs 3 days weekly outpatient clinic, and on average, up to 30-40 CHB patients are expected to visit the clinic weekly as newly referred cases or for follow-up. 507 CHB patients had visited the TASH liver clinic at least twice in the 12 months (i.e., from January 2020- January 2021).

The study population for this study was all CHB patients attending the TASH liver clinic for follow-up service during the data collection period. The study included; (1) patients with confirmed diagnosis of CHB infection (HbsAg-positive persistence for more than 6 months) and had at least two visit at the TASH liver clinic, (2) aged 18 years and above, (3) able to speak and understand either English, Amharic or Afan Oromo languages, and (4) understood the study objectives and voluntary to be interviewed. Patients with known cognitive or mental disorders and those who are seriously ill were excluded from the study.

The sample size was calculated using single proportion formula with the assumptions of confidence interval = 95%, critical value (Zα/2) = 1.96, and degree of precision (d) = 0.05. The population proportion (p) = 50% was used since no research was done in the same setting concerning knowledge and practice for preventing HBV household transmission. n = ( Z 2 × p × q ) / d 2

Where n = sample size, p = population proportion rate = (50%), since the proportion of patients coming to the clinic was unknown, Z = standard normal variable at the confidential level of 95%, d = margin of error, which is 5%, and q = 1-p. n = ( 1.96 2 × 0.5 × 0.5 ) / 0.05 2 n = ( 3.8416 × 0.25 ) / 0.0025 n = 0.9604 / 0.0025 n = 384.16 ≈ 384

Since the source population is less than 10,000, the sample size was adjusted using the correction formula; Nf = ni/(1 + ni/N) where ni = initial sample size, Nf = new sample size, N (total population) = 507. Therefore; Nf = 384/(1 + 384/507) Nf: 384/1.76 = 218 Nf = 218

Then 10% of the new sample size was added by considering for non-response rate.

→ (10/100) × 218 = 22. Therefore, the sample size for this study is approximately 22 + 218 = 240.

A simple random sampling method was used to recruit 240 adult patients with confirmed chronic hepatitis B infection from those who visited the TASH liver clinic during four months periods of data collection.

Independent variables were; the participant’s demographic details and clinical data that might influence the dependent variables. These includes; Age, sex, marital status, occupation, level of education, region, disease duration, duration of follow up at TASH, treatment status and if anybody else in the household is infected. Dependent variables were; the level of knowledge of transmission and prevention of HBV and the level of practices towards household transmission prevention of HBV.

Knowledge is defined as the fact or condition of being aware of something. ²⁰ In this study, it was used to assess patients’ awareness of modes of HBV transmission and how to prevent it. The overall knowledge of respondents was assessed using fourteen questions regarding HBV transmission and prevention. Each of the 14 knowledge questionnaires had three possible responses: yes, no, or don’t know. The responses were scored by assigning a value of 1 to correct answers and a value of 0 to wrong answers and don’t know. A total knowledge score was presented on a scale of 100, and to categorize knowledge score, the total score was dichotomized as high (≥75 out of 100 (≥11 out of 14)) and low to intermediate if <11(75%) using a top quartile score as the cut of point. ^{21, 22}

Practice is defined as; to carry out, to apply or to do or perform often, customarily, or habitually. ²³ In this study, it was used to assess the degree of implementation of recommended measures to prevent HBV transmission within the household. The practice of individual respondents regarding household transmission prevention of HBV was assessed by seven ‘yes’ or ‘no’ questions. Each correct response was given a score of “1” while an incorrect answer was given a score of “0”. The total score was categorized using a top quartile score, as good for a score between 6 and 7 points and fair to poor if <6(75%).

A standardized questionnaire was developed adopting items from previously validated tools used in studies on Knowledge of hepatitis B transmission and prevention. ^{18, 21, 24} The Original questionnaires were reviewed, and contextually relevant modifications were made to align with the Ethiopian health care setting and cultural context. The questionnaire was prepared in English and translated into Amharic and Afan Oromo Languages. A structured questionnaire containing 31 items with 3 sections, covering the socio-demographic and clinical characteristics of the patients (10 questions), patients’ knowledge related to HBV transmission and prevention (14 questions), and (7 questions) to assess the practice towards prevention of HBV household transmission were used for data collection. The questionnaire was validated by doing a pre-test on 10% of the sample before the actual data collection period. A necessary modification of the questionnaires was carried out based on the pre-test feedback. Furthermore, the reliability of the questionnaires was checked, and their using SPSS Cronbach Alpha value was 0.93 and 0.729 for questions of knowledge of transmission and prevention and prevention practice, respectively. The nurses who had access to patient’s medical record numbers were asked to select CHB patients and give their lists to the data collectors after routinely taking their vital statistics. A simple random sampling method selected the participants from the lists. Then Patients were invited to participate in the research while they were waiting for his/her turn at the follow-up clinic or after being seen by their doctors. The data collectors were the investigator and staff nurses, and medical interns. Adequate orientation was given to data collectors on the aim of the research, the content of the questionnaire, and the data collection process. The data was collected three days/week (i.e., during the clinic’s weekly service). The investigator also supervised the data collection processes regularly during the whole data collection period. The collected data was checked every day by the investigator for its completeness and consistency. A copy of full questionnaires used in this study has been uploaded as Extended Data.

Data were analyzed using SPSS version 26 statistical packages. Descriptive variables were expressed as frequency, percentages, mean, standard deviation, and abnormally distributed variables as the median. Bivariate analyses (independent t-test, chi-square & ANOVA) were conducted to test the associations between dependent and independent variables. The association was further assessed using regression analysis for the variables that showed significance in bivariate analysis. A P-value < 0.05 was considered to be statistically significant in all cases. Participants with missing data for the main outcome were not included.

Ethical approval for this study was obtained on 1 ^st of September 2021, from Addis Ababa University Collage of Health Sciences Department of Internal Medicine Ethics Committee located at Addis Ababa, Ethiopia. The study protocol was reviewed and approved by departmental research and ethics committee under supervision of Dr. Dawit Kebede and Dr. Abdurezak Ahmed. Although no formal reference number was issued initially due to internal record keeping practices, a documented approval was granted prior to commencement of the study and the most recent renewal was approved on April 29, 2025 under the reference number IMD/941/25.

All study participants were adults aged 18 years and above, with no known mental or cognitive disorders. Participants’ involvement in the study was voluntary, and a written informed consent was obtained from all participants after providing detailed information about the study’s objectives, procedures, risks and benefits. The Consent process was conducted in accordance with ethical approval granted by the ethics committee of the department. No personal identifiers were used on the data collection form. Collected data were only accessed by the investigators and confidentiality was be maintained at all levels of the study.

Of 240 sampled and eligible for interviews, only 229 chronic HBV patients were included in this study, making the response rate 95 percent. 156(68.1%) respondents were male and 73(31.9%) were female. Participants had a mean age of 39.8(±11) years. 183(79.9%) of them were married and 41(17.9) were single. The majority (71.1%) of respondents have had at least attended secondary education. 125(54.6%) participants were either government or private employed while 28(12.2%) had no job. About 2/3rd of participants (69%) were residents of Addis Ababa, while 21.8% were from Oromia regional state. The mean duration of illness from the time of diagnosis was 4.8(±4.2) years, and the mean duration of follow-up at TASH was 3.2(±2.7) years. Most of them (69%) have never received any specific treatment for HBV, and 92.1% of the participant had no additional household member infected with HBV.

The mean total knowledge score of 14 questions for HBV transmission and prevention was 79.1 (11.14(SD: ±2.6)), showing a high level of hepatitis B knowledge among participants. Nearly 2/3rd of participants (65%) showed a high level of knowledge. 90% percent of respondents knew HBV could be transmitted by having unprotected sex with a person infected with hepatitis B, while 28% of them were unaware of vertical transmission. Nearly 2/3rd of participants (65%) were aware of four main routes of HBV transmission (i.e., vertical, sexual contact, sharing injecting equipment, sharing toothbrushes or razor blades), and only 3 patients were unaware of any of the transmission routes. The three questions that were least likely to be answered correctly were about possibilities of transmission by; touching a person with hepatitis B (69%), by kissing a person with hepatitis B (52%), and through the air when a person with hepatitis B coughs or sneezes (67%). Most of the participants (96.5%) were aware that people with hepatitis B should tell their family members to get tested as Summarized in Table 1.

Mean total practice score of seven questions used to assess the practices towards prevention of household transmission was 4.7(SD: 1.79). Since some of questions were not applicable to some patients, only participants for whom all of question assessing practices were included to calculate mean practice score and to categorize practice. The total practice score was dichotomized as good (6-7) or fair to poor (<6). Accordingly, 39 (38.6%) patients were within the good practice range whereas 62 (61.4%) showed fair to poor practice towards HB prevention. When queried about specific preventive practices, most of the respondents (87%) answered they had disclosed their status of HBV infection to their spouse; about 2/3rd of participants said they encouraged their household members or sexual contacts to get tested; only a half of the respondents said they recommended HBV vaccination to identified unvaccinated household members and/or sexual contacts. Fifty-three (26%) respondents said they always use condoms when having sex with unvaccinated/unimmunized partners. Twenty-six (11%) said they had ever shared personal items (razors, toothbrushes, and/or nail scissors) with household members, while 109(83%) said they always cover their wounds as Summarized in Table 2.

Specific socio-demographic characteristics were associated with hepatitis B knowledge among participants. Bivariate analyses (independent t-test, chi-square & ANOVA) were conducted to test the associations between socio-demographic data and mean knowledge score of respondents. Three variables; age group, duration since diagnosis, and presence or absence of additional infected household members showed significant association with knowledge score. Significant predictors of knowledge were assessed using standard multiple regression. The three variables identified as significant predictors of mean knowledge score (age, duration since diagnosis, and other infected household members) were further analyzed by standard multiple regression. The results indicated that the younger age group, presence of additional infected household members, and longer duration since diagnosis as significant predictors of higher knowledge score (R2 = 0.106, F = 8.936, P < 0.001) as summarized in Table 3.

Factors associated with practice regarding HBV transmission prevention in the bivariate analyses were assessed using logistic regression ( Table 4). In Adjusted logistic regression, factors associated with the poor practice were; low level of education (OR: 5.218; 95%CI: 1.34-20.23; p = 0.017), being on anti-HBV treatment (OR: 3.582; 95%CI: 1.04-12.33; p = 0.043) and duration of follow up at TASH < 2years (OR: 2.93; 95%CI: 1.14-7.55; p = 0.025).

The findings of this study are subject to some limitations. It is not possible to exclude the possibility of selection bias based on willingness to be interviewed or of response bias based on respondent self-report that could not be verified by other means. The study was done on outpatients in a single public tertiary hospital, usually approached by low to middle-income populations. The high-income group usually uses these facilities in emergencies only. Hence the results of our research may not represent the entire population. Besides, the participants were recruited in clinical settings, and the result may over-represent people with CHB who are sufficiently motivated to seek clinical care for their infection. However, the high interview response rate for knowledge questions and random sampling are strengths of our study that should minimize selection bias.

We recommend comprehensive educational interventions using strategies and techniques shown to increase health literacy (by clinicians at outpatient clinics or Mass Media) are needed to improve the knowledge gap and misconception about HBV transmission identified in people with CHB infection. Any educational programs planned for this population should give special attention to the implementation of recommended prevention practices than simple awareness creation, with priority given to those with low education, <2 years of follow-up, and those on anti-hepatitis B treatment.