Vaccine uptake and immune responses to HBV infection amongst vaccinated and non-vaccinated healthcare workers, household and sexual contacts to chronically infected HBV individuals in the South West Region of Cameroon

<div><p>Background</p><p>HBV infection affects about 257 million people globally and Sub-Saharan Africa has the highest burden. The disease still constitutes a major public health problem despite the advent of preventive measures like the HBV vaccine. This study was aimed at identifying factors that influence vaccine uptake and the efficacy of administered vaccines among people at high risk of HBV infection.</p><p>Methods</p><p>This was a cross-sectional study conducted between January 2016 and December 2017. A pretested semi-structured questionnaire was used to capture information on sociodemographic and vaccination status from healthcare workers, household and sexual contacts to HBV infected people. HBV serological panel as well as quantitative anti-HBs ELISA test was done for all participants. Additional information was obtained from the institutions that administered the vaccines.</p><p>Results</p><p>A total of 265 participants with a mean age of 32.1±8.7 were enrolled. Eighty (30.2%) of them had received at least 1 dose of the HBV vaccine while 185 (69.8%) were unvaccinated. Healthcare workers were the most vaccinated (37%). Ignorance, negligence, fear of injection and the cost of the vaccine all contributed to poor vaccine uptake in the study population. Natural immunity was seen in 9 (3.4%) of the participants. Only 64.9% of the vaccinated participants attained the desirable level of anti-HBs (≥10mIU/ml) 1–2 months after ≥ 3 doses of the vaccine. Age, gender, obesity, alcohol and smoking were not significantly associated with poor immune responses. No standardized protocol was followed by the institutions administering the vaccine.</p><p>Conclusion</p><p>This study revealed very poor vaccine uptake and poor immune responses to the HBV vaccine in the study population and this should urge the health sector in Cameroon to intensify their sensitization on HBV vaccine, standardize the protocol for storing and administering the vaccine, subsidize the cost of the vaccine especially amongst healthcare workers and encourage anti-HBs post vaccination testing.</p></div

Age and gender distribution across the different groups of participants.

<p>Age and gender distribution across the different groups of participants.</p

Serological panel results for Participants who have taken ≥ 3 doses of the vaccine (n = 68).

<p>Serological panel results for Participants who have taken ≥ 3 doses of the vaccine (n = 68).</p

Level of HBV vaccine uptake among the different risk groups (n = 265).

<p>Level of HBV vaccine uptake among the different risk groups (n = 265).</p

Effect of time on anti-HBs concentration (after 3^rd dose of vaccine).

<p>Effect of time on anti-HBs concentration (after 3^rd dose of vaccine).</p

Serological panel results for non-vaccinated participants (n = 185).

<p>Serological panel results for non-vaccinated participants (n = 185).</p

Vaccinated participants collected 1–2 months after 3^rd dose and factors affecting vaccine response.

<p>Vaccinated participants collected 1–2 months after 3^rd dose and factors affecting vaccine response.</p

Non-vaccinated individuals and reasons for not taking the vaccine.

<p>NB: <i>Ignorance</i>: Not being aware of the fact that there is an HBV vaccine. <i>Negligence</i>: Aware of the HBV vaccine and its importance yet not vaccinated.</p

Summary of Anti-HBs concentrations for vaccinated participants who have received ≥ 3 doses of HBV vaccine (n = 68).

<p>Summary of Anti-HBs concentrations for vaccinated participants who have received ≥ 3 doses of HBV vaccine (n = 68).</p

Epidemiological factors associated with HBV infection and uptake of testing in south west region of Cameroon: What can be done to scale up HBV testing in our setting?

Hepatitis B infection affects millions of people globally, partly due to its high degree of transmissibility and asymptomatic nature. This study was aimed at identifying prevailing epidemiological factors associated with HBV infection and testing uptake in the South West region of Cameroon. This hospital-based case-control study enrolled HBV infected participants and "healthy" controls ≥18 years old. Venous blood collected from participants was used to conduct HBV panel test (HBsAg, anti-HBs, HBeAg, anti-HBe, anti-HBc). Data on demographic and behavioral risk factors as well as reasons for taking the HBV test for the first time were collected using a questionnaire. A total of 424 participants were enrolled (212 "healthy" controls and 212 HBV infected cases). Male sex (odds ratio [OR] = 2.08, p = 0.010), ≤ secondary education level (OR = 4.83, p<0.001), low-income level (OR = 3.79, p<0.001), rural settlement (OR = 2.17, p = 0.031), history of sexually transmitted infections (STI) (OR = 4.24, p<0.001) and ignorance of sexual partners HBsAg status (OR = 2.70, p = 0.003) all had an independent and significant association with HBV infection. Top 3 reasons for doing HBsAg test were free screening (40.3%), blood donation (15.0%) and administrative requirements (14.9%). HBV testing uptake and early detection can be improved if more sensitization and free/opportunistic screenings are implemented. A significant drop in the cost of HBV test could encourage more people to get tested