Immunoprophylaxis failure and vaccine response in infants born to mothers with chronic hepatitis B infection in Djibouti

BACKGROUND In endemic areas,vertical transmission of hepatitis B virus(HBV)remains a major source of the global reservoir of infected people.Eliminating mother-to-child transmission(MTCT)of HBV is at the heart of World Health Organization’s goal of reducing the incidence of HBV in children to less than 0.1%by 2030.Universal screening for hepatitis B during pregnancy and neonatal vaccination are the main preventive measures.AIM To evaluate the efficacy of HBV vaccination combined with one dose of immunoglobulin in children born to hepatitis B surface antigen(HBsAg)-positive mothers in Djibouti city.METHODS We conducted a study in a prospective cohort of HBsAg-positive pregnant women and their infants.The study ran from January 2021 to May 2022,and infants were followed up to 7 mo of age.HBV serological markers and viral load in pregnant women were measured using aVidas microparticle enzyme-linked immunosorbent assay(Biomérieux,Paris,France)and the automated Amplix platform(Biosynex,Strasbourg,France).All infants received hepatitis B immunoglobulin and were vaccinated against HBV at birth.These infants were closely monitored to assess their seroprotective response and for failure of immunoprophylaxis.Simple logistic regression was also used to identify risk factors associated with immunoprophylaxis failure and poor vaccine response.All statistical analyses were performed with version 4.0.1 of the R software.RESULTS Of the 50 pregnant women recruited,the median age was 31 years,ranging from 18 years to 41 years.The MTCT rate in this cohort was 4%(2/50)in HBsAg-positive women and 67%(2/3)in hepatitis B e antigen-positive women with a viral load>200000 IU/mL.Of the 48 infants who did not fail immunoprophylaxis,8(16%)became poor responders(anti-HB<100 mIU/mL)after HBV vaccination and hepatitis B immunoglobulin,while 40(84%)infants achieved a good level of seroprotection(anti-HB>100 mIU/mL).Factors associated with this failure of immunoprophylaxis were maternal HBV DNA levels(>200000 IU/mL)and hepatitis B e antigen-positive status(odds ratio=158,95%confidence interval:5.05-4958,P<0.01).Birth weight<2500 g was associated with a poor immune response to vaccination(odds ratio=34,95%confidence interval:3.01-383.86,P<0.01).CONCLUSION Despite a failure rate of immunoprophylaxis higher than the World Health Organization target,this study showed that the combination of immunoglobulin and HBV vaccine was effective in preventing MTCT of HBV.Therefore,further studies are needed to better understand the challenges associated with immunoprophylaxis failure in infants in Djibouti city.

H2 strain attenuated live hepatitis A vaccines:protective efficacy in a hepatitis A outbreak

AIM:To investigate the protective efficacy of H2 strain attenuated live hepatitis A vaccines (H2-strain vaccines) in hepatitis A (HA) outbreaks.METHODS:With the permission of their parents, 5551 pre-school and grade 1-3 primary school children were inoculated with 1 dose (10(6.5) TCID(50)) of H2 strain vaccines in a nonrandomized, controlled trial conducted in Fucheng County, Hebei Province in May 1997.Another 6485 children in the same grades and compatible in gender and age were enrolled as controls. Epidemiological and serological survey was conducted to evaluate the protective efficacy of the vaccines. ELISA was used to detect serum IgM anti-HAV.RESULTS:HA outbreak started in early May 1998, peaked in the middle of the same month, and lasted about 80 days. Overall 302 HA cases were found, 192(63.58%) were 5-9 years old. One vaccinee and 25 control cases were found to have hepatitis A, which account for 0.28% (1/356) and 5.92% (25/422) of all vaccinees and controls in the 14 villages, respectively. The protective efficacy of vaccines was 95.27% (95% CI: 85.83%-104.72%). In subjects tested for anti-HAV IgM from 13 villages, 1(0.40%) overt and 11(4.06%) asymptomatic HAV cases were found in 271 vaccinees but 21(6.69%) of overt and asymptomatic ones were found in 314 controls.CONCLUSION:H2 strain vaccines were excellent in preventing overt hepatitis A,but not so effective in preventing asymptomatic hepatitis A virus infection.A booster dose might be needed to get permanent reliable immunity.

Hepatitis E virus chimeric DNA vaccine elicits immunologic response in mice

AIM： To construct the plasmid pcHEV23 containing fragments of HEV ORF2 and ORF3 chimeric gene and to assess its ability to elicit specific immunologic response in mice. METHODS： The gene encoding the structural protein of HEV ORF2 fragment and full-length ORF3 was amplified by PCR. The PCR products were cloned into an eucaryotic expression plasmid pcDNA3. The resulting plasmid pcHEV23 was used as a DNA vaccine to inoculate BALB/c mice intramuscularly thrice at a dose of 100 or 200 ug. Mice injected with empty pcDNA3 DNA or saline served as control and then specific immune responses in the mice were detected. RESULTS： After 2-3 times of inoculation, all mice injected with pcHEV23 had anti-HEV IgG seroconversion and specific T lymphocyte proliferation. The lymphocyte stimulation index in the group immunized with pcHEV23 （3.1＋0.49） was higher than that in the control group （0.787±0.12, P〈0.01）. None in the control group had a detectable level of anti-HEV IgG. CONCLUSION： DNA vaccine containing HEV ORF2 and ORF3 chimeric gene can successfully induce specific humoral and cellular immune response in mice.

Potatoes Deliver Hepatitis Vaccine in Human Trials

马铃薯是人们再熟悉不过的一种普通蔬菜,但科学家新近研究证明,基因转录过的马铃薯中含有B型肝炎疫苗,服用后可提高人体对B型肝炎病毒(HBV)的免疫能力。科学家正继续研究如何将冷冻干藏的马铃薯作为辅佐性药物成分纳入抗肝炎的胶囊之中。小小土豆,不可轻瞧哦!

Potatoes Deliver Hepatitis Vaccine in Human Trials

近年来研究人员利用转基因植物培育抗病毒疫苗。这种方法既经济,又比利用细菌培育抗病毒疫苗的传统方式安全,因为植物中不含病毒。最近科学家利用转基因土豆培育出了抗B型肝炎疫苗,这对利用植物培育抗病毒疫苗具有重要意义。

Relationship between T-lymphocyte cytokine levels and sero-response to hepatitis B vaccines

AIM: To investigate the cellular defects by analyzing the (Th1/Th2) cytokine levels in vaccine responders and non-responders. METHODS: Peripheral blood mononuclear cell (PBMC) from responders and non-responders were stimulated with or with out recombinant HBsAg or PHA. Broad spectrum of cytokines viz (Th1) IFN-γ, IL-2, TNF-α, IL-12 and (Th2) IL-10, IL-4 were measured after in vitro stimulation with recombinant HBsAg and were compared with respective antibody titers. RESULTS: A significant decrease (P = 0.001) in Th1 and Th2 cytokines namely, IL-2, INF-γ, TNF-α and IL-10in non-responders was observed. The level of IL-4 was not significant between the three groups. Furthermore, despite a strong Th1 and Th2 cytokine response, the level of IL-12 was elevated in high-responders compared to other groups (P = 0.001) and demonstrated a positive correlation with anti-HBs titers and Th1 cytokine response. CONCLUSION: Our findings suggest that unrespon-siveness to recombinant hepatitis B vaccines (rHB) is multifactorial, including specific failure of antigen presentation or the lack of both T helper Th1 and Th2 response.

Immunogenicity and reactogenicity of a recombinant hepatitis B vaccine in subjects over age of forty years and response of a booster dose among nonresponders

AIM:The study was initiated to evaluate the reactogenicity and immunogenicity of a recombinant hepatitis B vaccine in age group >40 years and to study the response of a single booster dose in primary non-responders to the hepatitis B vaccination. METHODS:A total of 102 volunteers without markers of hepatitis B infection (negative for HBsAg,anti-HBc antibody, HBeAg and anti-HBs antibody) received 20μg of recombinant HB vaccine intramuscularly at 0,1,and 6 months.Anti HBs titers were evaluated by a quantitative Elisa kit at 90 and 210 days.A booster dose of 20μg HB vaccine was given after 6 months of the 3^(rd) vaccine dose to the 15 non- responders and anti-HBs titers were measured after i month. RESULTS:Seroprotection (anti-HBs GMT^3 10 IU/L) was achieved in 85.3 % (87/102) volunteers.The mean GMT titers of the vaccine responders was 136.1 IU/L.Of the seroprotected individuals,there were 32.4% (33/102) hyporesponders (anti- HBs titers <10-99 mIU/ml) and 52.9% (54/102) were responders (anti-HBs titers >100 IU/L).All the non-responders (15/15) responded to a single dose of the booster dose of recombinant HB vaccine and their mean anti-HBs antibody titers were more than 100.5 mIU/ml after the booster dose. CONCLUSION:Recombinant hepatitis B vaccine offers good seroprotection in the age group >40 years and has a good safety profile.A single booster dose after 6 months in primary non-responders leads to good seroprotective anti-HBs antibody titers.However,larger population based studies are needed to evaluate the role of a booster dose in selected group of non-responders and whether such an approach will be cost effective.

Construction and characterization of an experimental ISCOMS-based hepatitis B polypeptide vaccine

AIM: To characterize the biochemical and immunological properties of an experimental ISCOMS vaccine prepared from a novel therapeutic polypeptide based on T cell epitopes of HBsAg, and a heptatis B-ISCOMS was prepared and investigated. METHODS: An immunostimulating complexes(ISCOMS)-based vaccine containing a novel therapeutic hepatitis B polypeptide was prepared by dialysis method, and its formation was visualized by electron microscopy and biochemically verified by SDS-polyacrylamide gel electrophoresis. Amount of the peptide within ISCOMS was determined by Bradford assay, and specific CTL response was detected by ELISPOT assay. RESULTS: Typical cage-like structures of submicroparticle with a diameter of about 40nm were observed by electron microscopy. Results from Bradford assay showed that the level of peptide incorporation was about 0.33g.L(-1). At the paralleled position close to the sixth band of the molecular weight marker(3480kDa) a clear band was shown in SDS-PAGE analysis, indicating successful incorporation of polypeptide into ISCOMS. It is suggested that ISCOMS delivery system could efficiently improve the immunogenicity of polypeptide and elicit specific immune responses in vivo by the results of ELISPOT assay, which showed that IFN-gamma producing cells(specific CTL responses) were increased(spots of ISCOMS-treated group: 47+/-5, n =3; control group: 5+/-2, n =3). CONCLUSION: ISCOMS-based hepatitis B polypeptide vaccine is successfully constructed and it induces a higher CTL response compared with short polypeptides vaccine in vivo.

Evaluation of immunogenicity and reactogenicity of recombinant DNA hepatitis B vaccine produced in India

AIM： （1） To gain information on immune responses to an accelerated schedule of 0, 1, and 2 mo in paramedical staff and BDS students who are at an increased risk of getting hepatitis B infection and come under high risk groups. （2） To assess the efficacy and safety of En/vac- HB in different age groups, using genetically modified yeast strain Pichia pastoris, a new recombinant hepatitis B accine developed and manufactured in India. METHODS： A prospective, comparative, and single blinded trial of rapid （0, 1, and 2 mo） hepatitis B immunization schedulewas reported. A total of three hundred and seven （212 females and 95 males） healthy volunteers divided into three age groups （18-29, 30-39, and 40-49） were enrolled after screening for markers of hepatitis B. All the volunteers received 20 mg of the vaccine intramuscularly at 0, 1, and 2 mo. RESULTS： Geometric mean titers were calculated pre and post vaccination. Before immunization the GMT was 0.0124 mIU/mL. One month after the administration of the third dose of recombinant vaccine 296/307 （96.5%） subjects achieved seroprotective levels of anti-HBs. The geometric mean anti-HBs titers achieved after one month of the third dose was 2 560.0 mIU/mL. The geometric mean anti-HBs titer of males was 2 029.0 mIU/mL, while that of the females was 2 759.0 mIU/mL. In the age group of 18-29 years, anti-HBs titer was 3 025.0 mIU/ mL, while that in the age group of 30-39 years was 2 096.0 mlU/mL. In third age group of 40-49 years, anti- HBs titer was 1 592.0 mIU/mL. Hyper-responses （anti-HBs≥100 mIU/mL） were shown in 88.0% （271/307） of subjects. Eleven （3.5%） subjects responded poorly to the vaccine in the age group of 40-49 years. There was only mild pain at the site of injection otherwise there were no other adverse drug reactions （ADRs）. CONCLUSION： This vaccine （Enivac-HB） is safe and efficacious, providing significant protection after the third dose and rapid hepatitis B immunization schedule of 0, 1, and 2 mo can be recommended whenever rapid protection is the goal.

Primary Research of Immunological Mechanism of Combined Hepatitis A-Measles-Varicella Vaccine

To explore the primary humoral and cellular immunological mechanism of the combined hepatitis A-measles-varicella vaccine, the mice were inoculated with hepatitis A-measles-varicella vaccine by intraperitoneally and two weeks later, blood was collected to observe the mice＇s immunological status. Antibody level was measured to appraise the humoral immunity. At the same time, T lymphocyte surface marker, NK cell activity, LAK cell activity, delayed type hypersensitivity of skin, Mφ phagocytic function, mRNA level of cytokine IL-2 and IFN-γ plus lymphocyte transformation test were used to analyze the cellular immunity. The humoral immunity results show that the combined hepatitis A-measles-varicella vaccine produce the same antibody level as their corresponding univalent vaccine, and maintained fine immunogenicity and security. The result of cellular immunity shows that the combined vaccine could activate physical immunocyte, increase the regulative ability of cytokine, enhance the physical immune function and immune defense ability. The present research proved the security and better humoral and cellular immunity of combined hepatitis A-measles-varicella vaccine from the immunological point of view, which laid good foundation for further study and development.

Testing for hepatitis B virus alone does not increase vaccine coverage in non-immunized persons

AIM To determine whether hepatitis B virus(HBV)-testing could serve as a gateway to vaccinate non-immunized individuals in a low-prevalent country.METHODS Non-immunized subjects participating in a multi-center, HBV-testing campaign in Paris, France were identified and contacted via telephone 3-9 mo after testing in order to determine vaccination status. Vaccination coverage was evaluated in per-protocol(for all respondents) and intent-to-treat analysis(assuming all non-responders did not vaccinate).RESULTS In total, 1215/4924(24.7%) enrolled subjects with complete HBV serology were identified as nonimmunized and eligible for analysis. There were 99/902 successfully contacted subjects who had initiated HBV vaccination after screening: per-protocol, 11.0%(95%CI: 9.0-13.2); intent-to-treat, 8.2%(95%CI: 6.7-9.8). In multivariable analysis, vaccination was more likely to be initiated in individuals originating from moderate or high HBV-endemic countries(P < 0.001), patients with limited healthcare coverage(P = 0.01) and men who have sex with men(P = 0.02). When asked about the reasons for not initiating HBV vaccination, the most frequent response was "will be vaccinated later"(33.4%), followed by "did not want to vaccinate"(29.8%), and "vaccination was not proposed by the physician"(21.5%). Sub-group analysis indicated a stark contrast in vaccination coverage across centers, ranging from 0%-56%.CONCLUSION HBV-vaccination after HBV screening was very low in this study, which appeared largely attributed to physician-patient motivation towards vaccination. Increased vaccination coverage might be achieved by emphasizing its need at the organizational level.

THREE－YEAR FOLLOW－UP AFTER A SINGLE BOOSTER DOSE OF VACCINE IN THE NONRESPONDERS AND HYPORESPONDERS TO HEPATITIS B VACCINE

Immuuoresponsiveness of revacclnation in nonresponders and hyporesponders to hepatitis B vaccine was evaluated.10 nonresponders and kyporesponders as well as 18 normal responders to the primary vaccination were offered a 10μg dose or blood-derived vaccine in May 1989,three years after a 3-dose primary vaccine schedule,and were rollowed up and checked at 2,6,12 and 36 months after the booster dose.The results showed that Anti-HBs titre increased in both poor and normal responders,but the antibody level in nonresponders and hyporesponders was lower and the duration of persistence was much shorter,while the antibody GMT in normal responders remained above protective level at 36 months arter revaccination.Thererore,it is difficult to say,according to the data,that revaccination can satisfactorily boost anti-HBs level in the poor responders.

Elicitation of strong immune responses by a DNA vaccine expressing a secreted form of hepatitis C virus envelope protein E2 in murine and porcine animal models

AIM： To characterize the immunogenicity of a hepatitis C virus （HCV） E2 DNA vaccine alone or with a protein vaccine boost in murine and porcine animal models. METHODS： A DNA vaccine expressing a secreted form of HCV E2 protein was constructed and used to vaccinate mice and piglets with or without boosting with a recombinant E2 protein vaccine formulated with CpG ODN and 10% Emulsigen. The immunogenicity of HCV E2 vaccines was analyzed by ELISA for antibody responses, MTT assay for lymphocyte proliferation, ELISPOT for the number of interferon-γ secreting cells, and cytotoxic T lymphocyte assays. RESULTS： Intradermal injection of E2 DNA vaccine induced strong Th1-1ike immune responses in mice. In piglets, E2 DNA vaccine elicited moderate and more balanced immune responses. A DNA vaccine prime and protein boost vaccination strategy induced significantly higher E2-specific antibody levels and shifted the immune response towards Th2-1ike ones in piglets. CONCLUSION： A DNA vaccine expressing a secreted form of HCV E2 protein elicited E2-specific immune responses in mice and piglets. Recombinant E2 protein vaccination following DNA immunization significantly increased the antibody response in piglets. These HCV E2 vaccines may represent promising hepatitis C vaccine candidates for further investigations.

Modeling the Long-term Antibody Response and Duration of Immune Protection Induced by an Inactivated,Preservative-free Hepatitis A Vaccine(Healive)in Children

Objective Long-term seroprotection via the hepatitis A vaccine is essential for the prevention of disease from the hepatitis A virus(HAV).Due to documented difficulties during decade-long follow-ups after receiving vaccines,statistical-modeling approaches have been applied to predict the duration of immune protection.Methods Based on five-year follow-up data from a randomized positive-controlled trial among Chinese children(1–8 years old)following a 0,6 months vaccination schedule,a power-law model accounting for the kinetics of B-cell turnover,as well as a modified power-law model considering a memory-B-cell subpopulation,were fitted to predict the long-term immune responses induced by HAV vaccination(Healive or Havrix).Anti-HAV levels of each individual and seroconversion rates up to 30 years after vaccination were predicted.Results A total of 375 participants who completed the two-dose vaccination were included in the analysis.Both models predicted that,over a life-long period,participants vaccinated with Healive would have close but slightly higher antibody titers than those of participants vaccinated with Havrix.Additionally,consistent with previous studies,more than 90%of participants were predicted to maintain seroconversion for at least 30 years.Moreover,the modified power-law model predicted that the antibody titers would reach a plateau level after nearly 15 years post-vaccination.Conclusions Based on the results of our modeling,Healive may adequately induce long-term immune responses following a 0,6 months vaccination schedule in children via induction of memory B cells to provide stable and durable immune protection.

Safety and effi cacy of hepatitis A vaccine in children with chronic liver diseas

AIM： To study the safety and efficacy of hepatitis A vaccine （HAV） in children with chronic liver disease of various etiologies. METHODS： Eleven children with chronic liver disease and thirteen age- and sex-matched controls negative for HAV antibodies were vaccinated against hepatitis A after they gave their informed consent. Children with uncontrolled coagulopathy or signs of hepatic decompensation were excluded. The vaccine （Havrix： 720 ELISA units in 0.5 mL, from GlaxoSmithKline Biologicals） was given intramuscularly in the deltoid in 2 doses 6 mo apart. Children were tested for HAV antibodies one and six months after the ist dose and one month after the 2^nd dose. Total serum bilirubin, alanine aminotransferase （ALT）, and aspartate aminotransferase （AST） were determined immediately before and after one month of the 1st dose of the vaccine. RESULTS： Only 7 out of the 11 patients were positive for HAV antibodies after the 1^st dose of the vaccine, as compared to 100% of the controls. One month after the 2nd dose, all patients tested were positive for HAV antibodies. No deterioration in liver functions of patients was noted after vaccination. No adverse events, immediate or late, were reported by the mothers after each dose of the vaccine. CONCLUSION： Hepatitis A vaccine is both safe and effective in this small studied group of children with chronic liver disease. Given the high seroconversion rate, post-vaccination testing for HAV antibodies is not needed.

Immunogenicity of recombinant hepatitis B vaccine in treatment-nave and treatment-experienced chronic hepatitis C patients: The effect of pegylated interferon plus ribavirin treatment

AIM： To retrospectively evaluate the vaccinationinduced anti-HBs seroconversion rates in treatmentnaive and treatment-experienced chronic hepatitis C （CHC） patients. Also to prospectively evaluate the seroconversion rates in CHC patients during pegylated interferon （PEG） plus ribavirin （RIB） treatment. METHODS： Seventy treatment-naive CHC patients （group A）, 22 sustained virological responders-SVR following interferon （IFN） plus RIB treatment CHC patients （group B） and 121 healthy subjects （group C） had been participated in the same HBV vaccination schedule （20 μg, 0-1-6 mo）. Seroconversion was considered if anti-HBs levels were above 10 mIU/mL within 3 mo following the third dose of the vaccine. Moreover, we prospectively selected 30 non-cirrhotic CHC patients and evaluated them for the efficacy of the same vaccine schedule randomizing them in two groups： Group-1, 15 CHC patients received the first dose of the vaccine in parallel with the initiation of PEG plus RIB treatment and Group-2, 15 patients received the same vaccination schedule without concomitant treatment. Determination of anti-HBs was performed at mo 1, 2, and 7. Statistical analysis of data was based on ANOVA student＇s t-test and chi-square analysis （P 〈 0.05）. RESULTS： Fifty-eight of 70 group A patients （82.85%）, 20/22 group B （90.9%） and 112/121 healthy subjects （92.56%） had been seroconverted. The seroconversion rates were significantly higher in the control group than in treatment-naive CHC patients （P = 0.04）. The corresponding rates were comparable between group A and group B CHC patients （P = 0.38）. The vast majority of non-responders （10/14, 71.43%） had been infected by genotype-1 of HCV. The seroconversion rates were comparable between group 1 and 2 CHC patients at mo 1 （20% versus 26.7%, P = 0.67）, mo 2 （46.7% vs 60%, P = 0.46） and mo 7 （86.7% versus 93.3%, P = 0.54） of follow-up. CONCLUSION： The immunogenicity of HBV vaccine seems to be lower in CHC patients compared to healthy subjects. SVR following IFN plus RIB treatment does not affect the antibody response to HBV vaccine. Infection by genotype-1 seems to negatively influence the seroconversion rates. Vaccination against HBV during PEG plus RIB combination treatment is not beneficial in terms of anti-HBs seroconversion rates.

A Study on Long-term Efficacy and Immunologic Persistence of Hepatitis B Plasma Vaccine Made in China

In order to demonstrate the long term protective efficacy and immunologic persistence of domestically made hepatitis B plasma derived vaccine, 371 children had been followed up for 5 to 8 years after primary vaccination (10 μg×3). The results showed that the positive rate of antibody to hepatitis B surface antigen (anti HBs) in 371 subjects was 77.6% and the geometric mean titre (GMT) of anti HBs was 47.32 IU/L. The anti HBs positive rates in the subjects who had been vaccined for five, six, seven and eight years remained 83.91%, 73.68%, 81.25% and 72.24%, respectively, while the GMTs were 59.53, 43.64, 42.21 and 46.20 IU/L, respectively. The protective efficacy rate of hepatitis B vaccine was 94.26% if both HBsAg and anti HBc were considered as infective indicators, and 88.28%, if only HBsAg positive cases were taken into account. The study indicated that the domestically made hepatitis B vaccine could provide at least 5 to 8 years protection against hepatitis B infection.

Biodegradable Microspheres as Hepatitis B Vaccine Delivery Systems

In order to investigate the immunogenicity of the controlled-release microencapsulated hepatitis B vaccine in mice,polyethylene glycol-poly-dl-lactide (PELA) microspheres with entrapped HBsAg were prepared by double emulsion W/O/W based on solvent extraction methods. BALB/c mice were immunized with the encapsulated vaccine by oral feeding or injection. Blood samples were collected at 8 th, 10 th, 14 th and 24 th weeks, respectively, and the levels of antibody response were detected by ELISA.It was found that the scanning electron microscopy showed the prepared microspheres had smooth and spherical surface, suitable for vaccine delivery. Two groups of mice orally fed with the encapsulated or conventional recombinant vaccines, respectively, there sera showed no obvious difference in the IgG levels. At 14 th week, the group injected with a single dose of encapsulated vaccine had a similar level of IgG response to the group injected with two doses of the recombination vaccine. At 24 th week, the IgG levels of the group injected with two doses of encapsulated vaccine were higher than those of the group injected with two doses of the recombination vaccine. It concludes that Controlled-release microencapsulated hepatitis B vaccine possesses the feature of slowly releasing in vivo and long times immunogenicity.

Perception of Medical Students towards Hepatitis B Virus Infection and Hepatitis B Vaccination in a Private Tertiary Hospital in Jos North Local Government, Plateau State, Nigeria

Background: Prevention is one of the safe schemes against the high prevalence of viral Hepatitis. Negative perceptions or perceptions about the risks of hepatitis B among medical students and health care workers may influence the behavioral pattern and adoption of preventive measures against the virus and can affect the uptake of the Hepatitis B vaccine. This study assesses the perception of medical students towards Hepatitis B virus infection and Hepatitis B Vaccination in a Private Tertiary Hospital in Jos North Local Government, Plateau State, Nigeria. Methods: This was a descriptive cross-sectional study done in August 2021 among 236 clinical medical students using a multistage sampling technique. Data was collected using an interviewer-administered structured questionnaire and analysed using the IBM SPSS 28 (Statistical Package for the Social Sciences). Ethical approval was granted by Bingham University Teaching Hospital, Ethics Committee, Jos, Plateau State. Results: Two-thirds of respondents were of the opinion that they are at risk of contracting HBV. Half were of the opinion that the risk is very much while a third believed the risk is moderate. Among those who think they are not at risk of contracting HBV, the majority felt so because they are vaccinated while 10.3% believe that they are safe. 43.2% of respondents think that HBV Vaccine is very effective in preventing HBV infection while 39.8% think it is slightly effective, and 7.6% think it is not effective. Almost all respondents, 99.2% are of the opinion that HBV Vaccination is important for students while 0.8% think it is not important. The majority of the respondents at 95.8% were willing to be screened for HBV. The majority (85.6%) of respondents are willing to pay for HBV Vaccine as against 14.4% of respondents who are not willing to pay. Conclusion: Summarily, 21 (8.9%) of the students had a negative perception of Hepatitis B Vaccination, and 215 (91.1%) had a positive perception of Hepatitis B Vaccination. Perception-sustaining events like seminars, workshops, road shows, and campaigns should be organized among students and health workers.