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.

Immune response to an indigenously developed r-Hepatitis B vaccine in mixed population: Study of an accelerated vaccination schedule

AIM: To establish the safety and efficacy of an indigenously developed r-hepatitis B vaccine using an accelerated schedule and to highlight the social awareness and commitment in preventing the spreading of hepatitis B virus infection. METHODS: The study was a multicentric, double blind, randomized (3:1) study using three doses of vaccine immunization schedule (20μg for those above 10 years old and 10 μg for those below 10 years old) on d 0, 30 and 60. One hundred and sixty-six subjects were enrolled (87 males and 76 females aged 5-35 years). The main outcome measure was assessment of immunogenicity and safety. RESULTS: A 100% seroconversion response was observed on the 30th d after the 1st injection in both the experimental groups. The sero-protection data reported a 41.2-65.6% response on the 30th d after the 1st injection and reached 100% on the 60th d. Descriptive statistical analysis showed a geometric mean titer value of 13.77 mIU/mL in the test (BEVAC) group and 10.95 mlU/mL in the commercial control (ENGERIX-B) group on the 30th d after the 1st injection. The response on the 60th d showed a geometric mean titre value (GMT) of 519.84 mlU/mL in the BEVAC group and 475.46 mlU/mL in the ENGERIX-B group. On the 90th d, the antibody titer response was observed to be 2627.58 mlU/mL in the BEVAC group and 2272.72 mlU/mL in the ENGERIX-B group. Two subjects in each group experienced pains at injection site after the first vaccination. A total of six subjects in both groups experienced a solicited adverse reaction, which included pains, swelling and redness at the injection site, three subjects in the group-B had a pain at the injection site after the third dose. No other serious adverse events occurred and no dose-related local or general symptoms were observed during the study. CONCLUSION: The vaccine is safe, efficacious and immunogenic in comparison with the well documented ENGERIX-B.

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.

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.

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.

ASSOCIATION OF GENETIC BACKGROUND WITH NON-ANDHYPORESPONSIVENESS TO HEPATITIS B VACCINE

HBV infection data of so first degree relatives from hepatitis B vaccine nonresponderand hyporesponder families stere compared 'vith those of 79 first degree relatives from high responder families. For further observation of their antibody response. those without the vaccination lwfore, and negative for HBsAg, anti-HBs and anti-HBc, or 'vith isolated ic'v anti-HBs (S/N M 10 )were given three 10 ig doses of hepatitis B vaccine at 0, 1 .6 months. The results Showed that. in thefirst degree relatives of nonresponders and hyporesponders, anti-HBs seroconversion rate and GMTwere lower (P > 0. 05), and the distribution or detected anti-HBs levels was significantly differentfrom that of the rirst degree relatives or high respondrs. In addition, before the vaccination. theHBV infection rate or the former was remarkably higher (33. 75% VS 15. 19% ), and the antibodyGMT of those positive ror anti-HBs was significantly ic'ver. This finding suggested that genetic background may play an important role in the n on -a nd-typo res ponsi yeness to hepat it is B vacc me.

Vaginal Delivery and Breastfeeding Benefit Infant Immune Response to Hepatitis B Vaccine:A Prospective Cohort Study

Background and Aims:Natural vaginal delivery and breastfeeding favor the development of a strong immune system in infants,and the immune response of infants to vaccines is closely related to their immune system.This large prospective cohort study aimed to explore the effects of delivery and feeding mode on infant’s immune response to hepatitis B vaccine(HepB).Methods:A total of 1,254 infants who completed the whole course of HepB immunization and whose parents were both HBsAg negative were enrolled from infants born in Jinchang City during 2018-2019 by cluster sampling method.Results:Twenty(1.59%)of the 1,254 infants were nonresponders to HepB.Among the other 1,234 infants,10.05%(124/1,234),81.69%(1,008/1,234)and 8.27%(102/1,234)of infants had low,medium,and high responses to HepB,respectively.Logistic regression analysis showed that cesarean section(OR:8.58,95%CI:3.11-23.65,p<0.001)and birth weight<3.18 kg(OR:5.58,95%CI:1.89-16.51,p=0.002)were independent risk factors for infant nonresponse to HepB,and cesarean section(OR:7.63,95%CI:4.64-12.56,p<0.001),formula feeding(OR:4.91,95%CI:1.47-16.45,p=0.001),maternal antiHBs negativity(OR:27.2,95%CI:10.67-69.35,p<0.001),paternal non-response history of HepB(OR:7.86,95%CI:2.22-27.82,p=0.014)and birth weight<3.22 kg(OR:4.00,95%CI:2.43-6.59,p<0.001)were independent risk factors for infant low response to HepB.In cases where birth weight and genetic factors are unmodifiable and maternal anti-HBs effects are controversial,it makes sense to enhance infant response by changing delivery and feeding patterns.Conclusions:Natural vaginal delivery and breastfeeding are beneficial to the infant’s immune response to HepB.

Hepatitis B Vaccination in Medical and Dental Students: A Cross-Sectional Study

Background: Medical and dental students are at risk of Hepatitis B Virus (HBV) infection. The study aimed to assess the vaccination status against Hepatitis B Virus of students in clinical and non-clinical years of a private medical and dental college, and their knowledge, attitude, and awareness about the subject. Methods: A cross-sectional study was conducted using a pretested, self-administered questionnaire among 203 medical and dental students of CMH Lahore Medical College and Institute of Dentistry (CMH LMC & IOD) in Lahore, Pakistan. Participants were evaluated for their knowledge and vaccination status against Hepatitis B Virus. Students were considered to be fully vaccinated (recipients of 3 doses), partially vaccinated (recipients of 1 or 2 doses), and unvaccinated. Comparisons were made between students of clinical and non-clinical years. Data was entered and analysed using Statistical Package for the Social Sciences (SPSS) version 23. Results: Only 66% (n = 134) of the 203 participants had ever received a Hepatitis B Virus vaccine out of which a meagre 17.2% (n = 35) were fully vaccinated. No significant difference was found in vaccine uptake between students of clinical and non-clinical years (p-value = 0.181) despite significant differences seen in the knowledge of vaccination schedule (p-value = 0.001), the prevalence of needle-stick injuries (p-value = 0.001), and knowledge of protocols to be followed after a needle-stick injury (p-value = 0.001). Conclusion: Our study found that a large proportion of the student population is vulnerable to HBV infection. There is a need to create awareness regarding the subject to increase vaccine uptake. HBV vaccination should be offered to all currently enrolled students and be made mandatory at the time of admission in the future.

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.

A pilot study on the combined therapy of granulocyte-macrophage colony-stimulating factor and hepatitis B vaccine on chronic hepatitis B virus carrier children

Objective To observe the efficacy of treating intrauterine infected chronic hepatitis B virus (HBV) carrier children with a combination of granulocyte macrophage colony stimulating factor (GM CSF) or hepatitis B immunoglobulin (HBIG) plus recombinant hepatitis B vaccine (rHBvac) Methods A total of 27 chronic HBV infected children, who were born to HBV carrier mothers and received hepatitis B immunoprophylaxis at birth, were randomized into 2 groups: one receiving a combined therapy of 50 μg of GM CSF plus 10 μg of rHBvac injected intramuscularly at the same location (GM CSF group, 14 children) or 200 IU HBIG and 10 μg rHBvac in different muscles (HBIG group, 13 children) on a monthly four dose schedule HBV DNA quantification and other HBV serological markers were tested before and after the four dose therapy Results Twelve children in each group completed the study Of them, 3 children in the GM CSF group and 4 in the HBIG group had elevated serum alanine transaminase (ALT) before the trial, and then 2 in each group became ALT normal after the treatment Before the therapy, hepatitis B e antigen (HBeAg) positivity was found in nine children in the GM CSF group and 10 in the HBIG group One from each group had an HBeAg/anti HBe seroconversion after the treatment The quantity of HBV DNA was significantly lower after the treatment ( P =0 023) in GM CSF group, but was not significantly reduced in HBIG group No subjects were found to be negative for hepatitis B surface antigen (HBsAg) after the treatment, and no serious adverse events occurred in either group Conclusion Combined GM CSF and rHBvac therapy inhibit HBV replication in carrier children who were not protected after treatment with immunoprophylaxis

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.

Field epidemiological and experimental study on relationship between genetic factor and nonresponse or hyporesponse to hepatitis B vaccine

Objective To evaluate the role of genetic factor in the development of nonresponder or hyporesponder to hepatitis B vaccine in Chinese people from field epidemiology and experimental study Methods Six hundred and thirty four susceptible healthy students were vaccinated with three doses of plasma derived hepatitis B vaccine Twenty nine non or hypo responders (subjects) and 30 hyperresponders (controls) as well as their 80 and 79 first degree relatives were determined and recruited in the study The first degree relatives of subjects and controls were then immunized with hepatitis B vaccine and followed up On the basis of the above results, alleles of HLA A,B,C,DR and DQ locus were further detected in the two groups Results The non and hypo response rate in immunized students was 4 6% (29/634) After administered with hepatitis B vaccine, the first degree relatives of the subjects displayed a 17 9% frequency of nonresponsiveness, higher than in the controls The phenotype frequency of HLA DR7 and B54 was 52 2% and 21 7% in subjects, 9 1% and 0 0% higher than in controls, respectively The extended haplotype B54 DR7 was more frequent in the former (17 0%) than in the latter (0 0%) ( P <0 01) Conclusion These results demonstrated that the genetic factor was likely associated with the non and hypo response to hepatitis B vaccine in Chinese people

Protective Effect of Neonatal Hepatitis B Vaccine Against HBV Breakthrough Infection in Children with Leukemia:A Real-world Study

Background and Aims:Hepatitis B vaccine is the most effective preventive measure against hepatitis B virus(HBV)infection.However,the risk of HBV breakthrough infection in fully immunized children(neonatal hepatitis B immunization)who receive immunosuppressive therapy and transfusion of blood components is not well characterized.In this real-world study,we aimed to investigate the immune protection conferred by neonatal hepatitis B vaccine in children with acute lymphoblastic leukemia(ALL)who were treated with immunosuppressive therapy and blood component transfusions.Methods:Children with ALL who had received all three doses of neonatal hepatitis B vaccine were included in this study.HBV seromarkers were detected before and after the initiation of immunosuppressive therapy.Results:A total of 1,011 children with ALL who were fully vaccinated against hepatitis B in infancy before the initiation of immunosuppressive therapy were eligible for inclusion.HBV infection was detected in four of 410 children(0.98%)with an HBsAg test after the initiation of immunosuppressive therapy.The median interval from treatment initiation was 19 months.Conclusions:Three doses of neonatal hepatitis B vaccine conferred adequate protection.In endemic regions,there is a low risk of HBV breakthrough infection in fully immunized children with immunosuppressive therapy.

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.

LONG-TERM IMMUNOGENICITY AND EFFICACY OF RECOMBINANT YEAST DERIVED HEPATITIS B VACCINE FOR INTERRUPTION OF MOTHER-INFANT TRANSMISSION OF HEPATITIS B VIRUS

Recombinant DNA Yeast-Derived Hepatitis B Vaccine (RYHB vaccine) is comparable to and can replace Plasma-Derived Hepatitis B Vaccine (PHB vaccine) for the prevention of mother-nfant transmission of hepatitis B virus (HBV), but the duration of immune efficacy of RYHB vaccine is not clear. This study indicates the long-term efficacy for the prevention of mother-infant transmission of HBV. One hundred and six neonates born to HBsAg-arrier mothers with HBeAg positive were randomly divided into two groups, one receiving 20 μg per dose of RYHB vaccine and the another receiving 20 μg per dose of PHB vaccine on the day of birth, at 1 month and at 6 months (three times). Physical examination and blood tests were performed for all infants at 6, 12, 24, 36, 48 and 60 months of age. The results showed that the protective efficacies at 6, 12, 24, 36, 48 and 60 months were 67%, 75%, 63%, 62%, 57% and 56%, respectively for the RYHB vaccine group and 58%, 76%, 51%, 41%, 24% and 18%, respectively for the PHB vaccine group. The protective efficacy was notably significant in the last two years. The study indicates that the duration of protective efficacy is over 5 years with RYHB vaccine, being longer than that of PHB vaccine. These recipients of RYHB vaccine showed no side effects, and the vaccine is regarded as safe and effective.

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.

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.

Safety Observation Study on Haemophilus Influenza Type B Conjugate Vaccines Injected at Different Sites in Chinese Infants

In the present study, the safety of Hoemophilus influenza type b conjugate vaccines inoculated in the upper arm deltoid and vastus lateralis muscle was evaluated. 680 infants aged 2-5 months and 6-12 months were selected to be the research subjects in whom the Hib conjugate vaccines were inoculated by injection in the upper arm deltoid and vastus lateralis muscle, respectively. The safety analysis indicated that there were no statistic differences in the incidence rates of adverse reactions when the Hib conjugate vaccines were inoculated at different sites. So we concluded that the safety of inoculation injection of Hib conjugate vaccines in vastus lateralis muscle was the same as that inoculated in the upper arm deltoid.