Long-term efficacy of plasma-derived and recombinant hepatitis B vaccines in a rural township of Central Taiwan

The seroepidemiology of isolated core antibody against hepatitis B among Taiwanese adults - A large hospital-based study

BACKGROUND/PURPOSE

This study aims to investigate the prevalence of isolated core antibodies against hepatitis B (IAHBc) in different birth cohorts using a large medical record database.

METHODS

Hepatitis B viral serological test data were collected from a chart cloud database at a medical center in Taiwan between January 2006 and December 2018. The data collected included birth year, sex, hepatitis B viral markers (HBsAg, anti-HBs or anti-HBc), and hepatitis B vaccination records. Enrolled patients were grouped according to their birth year into three categories: ≤ 1986, 1987-1992, and ≥ 1993, which correspond to no neonatal hepatitis B immunization, plasma-derived HB vaccine (PDHBV), and recombinant hepatitis B vaccine (RHBV), respectively. Prevalence of hepatitis B viral seromarkers, including IAHBc, was calculated by sex, age groups, and birth cohorts. Those who underwent repeated hepatitis B serology tests were included for further analysis to follow up their serostatus.

RESULTS

A total of 117,335 adults with complete hepatitis B serologic data were analyzed. Among them, 6641 individuals (5.7 %) were found to have IAHBc. The prevalence of IAHBc was 11.4 %, 0.8 %, and 0.3 % among those born before 1986, between 1987 and 1992, and after 1992, respectively. Among the 690 subjects with repeated blood tests and complete hepatitis B serologic data, 551 cases (79.9 %) remained IAHBc. The other cases included resolved infection status (13.9 %), seronegativity for three HB seromarkers (3 %), and carrier of hepatitis B virus (2.3 %).

CONCLUSION

The management of individuals with IAHBc should be tailored to their age, vaccination status, and risk factors for occult hepatitis B viral infection.

Epidemiology of Chronic Hepatitis B Infection in the Cohort of College Students with Vaccination in Taiwan

After the mass vaccination project in Taiwan, the prevalence of the hepatitis B virus (HBV) infection for the college-aged population of 18 to 21 years is uncertain. We aimed to investigate the prevalence of hepatitis B markers in different birth cohorts. A total of 38,075 students in universities in Kaohsiung area undergoing entrance examinations between July 2006 to September 2020 were included. Seroprevalence of the hepatitis B surface antigen (HBsAg) and hepatitis B surface antibody (anti-HBs) status and laboratory data were collected. The seropositive rate of HBsAg was less than 1% for students born after 1991. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST), were significantly higher, and body mass index (BMI) was significantly lower in HBV carriers compared to those who were not carriers (all p < 0.001). Multivariate logistic regression showed that age, male, higher BMI, and positive HBsAg were risk factors of abnormal ALT value. A decrease in the positive rate of anti-HBs which was significantly higher in the cohort of plasma-derived vaccines than recombinant vaccines was found. We concluded that there were decreasing trends in seropositive rates of HBsAg and anti-HBs for students of the college-aged population in the Kaohsiung area. The status of HBsAg was a predictive factor of abnormal ALT levels. The period effect on anti-HBs seropositivity for DNA recombinant vaccine somehow existed.

Insights into induction of the immune response by the hepatitis B vaccine

After more than four decades of hepatitis B virus (HBV) vaccine implementation, its safety and efficacy in preventing HBV infection have been proven and several milestones have been achieved. Most countries have included HBV immunization schedules in their health policies and progress has been made regarding universalization of the first HBV vaccine dose at birth. All of these actions have significantly contributed to reducing both the incidence of HBV infection and its related complications. However, there are still many drawbacks to overcome. The main concerns are the deficient coverage rate of the dose at birth and the large adult population that has not been reached timely by universal immunization. Additionally, the current most widely used second-generation vaccines do not induce protective immunity in 5% to 10% of the population, particularly in people over 40-years-old, obese (body mass index > 25 kg/m²), heavy smokers, and patients undergoing dialysis or infection with human immunodeficiency virus. Recently developed and approved novel vaccine formulations using more potent adjuvants or multiple antigens have shown better performance, particularly in difficult settings. These advances re-launch the expectations of achieving the World Health Organization’s objective of completing hepatitis control by 2030.

Outcomes of Hepatitis B Immunoglobulin and Hepatitis B Vaccination in High-Risk Newborns Born to HBeAg-positive Mothers

BACKGROUND

To evaluate the protective efficacy of a hepatitis B (HB) vaccination program in Taiwan among high-risk children.

MATERIAL AND METHODS

Children born to HBeAg-positive mothers from 2001 to 2010 were invited back. Blood samples for hepatitis B virus (HBV) seromarkers were taken and the children underwent hepatobiliary ultrasonography. Perinatal factors including delivery mode and vaccination history were collected from their medical records. According to the results of HBV serological markers, the children were initially classified into five groups: HBV naïve, HB vaccine responder, HBsAg carrier, recovered from HBV infection, and anti-HBc-positive alone. Children in the HBV naïve and anti-HBc-positive alone groups who presented with an anamnestic response after a booster HB vaccine were re-assigned to the vaccine responder and recovered from infection groups, respectively.

RESULTS

All of the 196 enrolled children received postnatal hepatitis B immunoglobulin (HBIG) and HB vaccinations, of whom one was HBV naïve (0.5%), 109 were vaccine responders (55.6%), 21 were carriers (10.7%), and 65 recovered from infection (33.2%). Among the 21 carriers, 14 (66.7%) presented in the immunotolerant phase. Cesarean section was the only significant perinatal factor between the carriers (5.3%) and those who recovered from infection (37.7%) (p=0.007).

CONCLUSIONS

In this study, there was a 43.9% HBV infection rate and 10.7% HBsAg carrier rate in high-risk Taiwanese children even after receiving HBIG and HB vaccinations. Cesarean section may protect newborns from becoming HBsAg carriers, while HBV genotype and time of HBIG injection did not contribute to the HBV carrier rate.

The positive rates of hepatitis B surface antibody in youths after booster vaccination: a 4-year follow-up study with large sample

BACKGROUND

Hepatitis B virus (HBV) infection is still a public issue of the world. Hepatitis B vaccination is widely used as an effective measure to prevent HBV infection. This large-sample study aimed to evaluate the positive rates of hepatitis B surface antibody (anti-HBs) in youths after booster vaccination.

METHODS

A total of 37,788 participants were divided into two groups according to the baseline levels of anti-HBs before booster vaccination: the negative group (anti-HBs (-)); the positive group (anti-HBs (+)). Participants were tested for anti-HBs levels after receiving a booster vaccine 1 year and 4 years.

RESULTS

The positive rates of anti-HBs were 34.50%, 73.8% and 67.32% before booster vaccination at 1 year and 4 years after vaccination, respectively. At four years after the booster vaccination, the positive rates of 13 to 18 years were 47.54%, which was the lowest level among all youths age groups. In the anti-HBs (-) group, the positive conversion rates of anti-HBs were 74.62% at 1 year after receiving a booster vaccine, and 67.66% at 4 years after vaccination. In the anti-HBs (+) group, the positive maintenance rates of anti-HBs were 70.16% after 1 year, and 66.66% after 4 years. Compared with the baseline anti-HBs (+) group, the positive rates of the baseline anti-HBs (-) group were higher at 1 year and 4 years after receiving the booster vaccine.

CONCLUSIONS

 The positive rates of anti-HBs declined over time, especially the positive maintenance rates were the lowest at age of 13 to 18 years.

Hepatitis B and pertussis antibodies in 4- to 5-year-old children previously vaccinated with different hexavalent vaccines

In randomized active-comparator controlled studies, DTaP5-HB-IPV-Hib showed comparable immunogenicity and safety to other licensed vaccines. This study assessed persistence of anti-hepatitis B surface antigen (HBs) and anti-pertussis antibodies, when children were 4 to 5 years of age, 3 to 4 years after initial infant/toddler hexavalent vaccination. This was an extension of 2 European studies in which infants/toddlers received either DTaP5-HB-IPV-Hib or DTaP3-HB-IPV/Hib on a 2 + 1 or 3 + 1 schedule. Primary endpoints included percentages with anti-HBs ≥10 mIU/mL, and anti-pertussis toxin (PT), anti-filamentous hemagglutinin (FHA), anti-pertactin (PRN), and anti-fimbriae types 2 & 3 (FIM) greater than or equal to the lower limit of quantitation (LLOQ). One month after 2 + 1 or 3 + 1 dosing, nearly all toddlers had anti-HBs ≥10 mIU/mL, and responded to the received pertussis antigens. Approximately 3 to 4 years later, 65.8%-70.2% in the DTaP5-HB-IPV-Hib and 82.0%-83.7% in the DTaP3-HB-IPV/Hib groups, respectively, had anti-HBs ≥10 mIU/mL. Percentages of children with pertussis antibodies above LLOQ after 2 + 1 dosing were 58.4% and 41.5% (anti-PT), 80.9% and 88.3% (anti-FHA), 66.1% and 72.6% (anti-PRN), and 94.4% and 3.3% (anti-FIM), in the DTaP5-HB-IPV-Hib and DTaP3-HB-IPV/Hib groups, respectively. This study demonstrated, as expected, waning of hepatitis B and pertussis antibodies during the 3 to 4 years after completion of a 3 + 1 or 2 + 1 hexavalent vaccination schedule. Nonetheless, anti-HBs levels ≥10 IU/mL and detectable antibodies against acellular pertussis antigens persisted in most study participants. The implications of these findings for the long-term prevention of hepatitis B and pertussis are further discussed.

Doses of hepatitis B revaccination needed for the seronegative youths to be seropositive to antibody against hepatitis B surface antigen

OBJECTIVES

To determine the required hepatitis B vaccine doses for subjects who were seronegative for three hepatitis B seromarkers during their youth who wish to have seroprotective antibodies against the hepatitis B surface antigen (anti-HBs).

METHODS

We conducted a retrospective cohort study. From 2012 to 2015, graduate school students born after 1986 who were seronegative for three hepatitis B virus seromarkers at college entrance (n = 1037) were recruited. Four groups of subjects received zero to three doses of a hepatitis B vaccine booster at their free willingness, and their anti-HBs titre were measured at their graduate school entrance. Very low and extremely low antibody titres against the hepatitis B surface antigen were elucidated by graphic inference to determine the required booster dose cut-off value for seropositivity after revaccination.

RESULTS

The anti-HBs seropositive rates in the four groups of subjects receiving the hepatitis B booster vaccine(s) were 17.7%, 52.1%, 78.6% and 90.9% for those receiving zero, one, two and three doses, respectively. In subjects with very low antibody titres against the hepatitis B surface antigen after one dose of the vaccine booster and subjects with an extremely low titre after two doses of the booster, the seropositive rates reached 95% at the cut-off value of 3 mIU/ml.

CONCLUSION

A seropositive rate of at least 95% can be reached by the administration of two hepatitis B booster doses to youths with extremely low antibody titres against the hepatitis B surface antigen (<3 mIU/ml) and administering one dose to those with very low titres (3-10 mIU/ml) at college.

Factors That Influence the Immune Response to Vaccination

There is substantial variation between individuals in the immune response to vaccination. In this review, we provide an overview of the plethora of studies that have investigated factors that influence humoral and cellular vaccine responses in humans. These include intrinsic host factors (such as age, sex, genetics, and comorbidities), perinatal factors (such as gestational age, birth weight, feeding method, and maternal factors), and extrinsic factors (such as preexisting immunity, microbiota, infections, and antibiotics). Further, environmental factors (such as geographic location, season, family size, and toxins), behavioral factors (such as smoking, alcohol consumption, exercise, and sleep), and nutritional factors (such as body mass index, micronutrients, and enteropathy) also influence how individuals respond to vaccines. Moreover, vaccine factors (such as vaccine type, product, adjuvant, and dose) and administration factors (schedule, site, route, time of vaccination, and coadministered vaccines and other drugs) are also important. An understanding of all these factors and their impacts in the design of vaccine studies and decisions on vaccination schedules offers ways to improve vaccine immunogenicity and efficacy.

Early and long term anamnestic response to HBV booster dose among fully vaccinated Egyptian children during infancy

OBJECTIVE

To evaluate early and long term anamnestic response to a booster dose of HBV vaccine among non-seroprotected children.

SUBJECTS AND METHOD

A national community based project was carried out on 3600 children aged 9 months to 16 years, fully vaccinated during infancy. They were recruited from 6 governorates representing Egypt. It revealed that 1535 children (42.8%) had non sero-protective anti-HBs (<10 IU/L) and were HBsAg or anti-HBc negative. A challenging dose of 10 μg of mono-valent Euvax HBV vaccine was given to 1121/1535 children. Quantitative assessment of anti-HBs was performed to detect early (2-4 weeks) and long term (one year) anamnestic responses.

RESULTS

Early anamnestic response developed among 967/1070 children (90.3%).Children having detectable anti-HBs (1-9 IU/L) significantly developed early anamnestic response (90%) compared to 85% with undetectable anti-HBs (<1 IU/L), P < 0.001. Multiple logistic analysis revealed that undetectable anti-HBs, living in rural residence and children aged 15-16 years were the most significant predicting risk factors for the absence of early anamnestic response (<10 IU/L), with AOR 2.7, 2.7 & 4.7 respectively. After one year, long term anamnestic response was absent among 15% of children who previously showed early response. Poor early anamnestic response and undetectable pre-booster anti-HBs were the significant predicting risk factors for absent long term anamnestic response, with AOR 18.7 & 2.7 respectively.

CONCLUSION

Immunological memory for HBV vaccine outlasts the presence of anti- HBs and HBV vaccination program provides effective long term protection even in children showing waning or undetectable concentrations of anti-HBs. This signifies no need for a booster dose especially to healthy children.

Seroprevalence of hepatitis B virus in Taiwan 30 years after the commencement of the national vaccination program

Background

In this study, the long-term efficacy of hepatitis B virus (HBV) vaccination was assessed using seroprevalence and an age–period–cohort (APC) model of HBV seromarkers among university entrants 30 years after the introduction of the national neonatal HBV vaccination program in Taiwan.

Methods

In total, data of 17,611 university entrants who underwent university entrance health examinations between 2005 and 2016 were included. The seroprevalence of the HBV surface antigen (HBsAg) and the levels of the antibody against the HBV surface antigen (anti-HBs) in each year group and sex were calculated. The levels of the antibody against the HBV core antigen were examined only for 2012 and 2016. The APC model was used to analyze the HBV carrier rates.

Results

The chronic HBV infection (HBsAg positivity) rate decreased from 9.7% in university students born before June 1974 to <1.0% in students born after 1992. The prevalence of anti-HBs positivity declined, particularly between the 1984–1988 cohort (78.2%–53.2%) and the 1990–1994 cohort (60.6%–44.4%). Our APC model revealed that the chronic HBV carrier rate among the student population was affected significantly by age, period, and cohort (P < 0.001).

Conclusions

HBV vaccination is one of the most effective strategies for preventing HBV infection. However, for complete eradication of HBV infection, the development of strategies that detect vaccination failure more effectively than current strategies do and early implementation of appropriate treatments are both necessary.

Higher disappearance rate of anti-HBs in Taiwanese freshers neonatally vaccinated with recombinant yeast hepatitis B vaccine

BACKGROUND & AIM

The aim of this study was to compare the long-term efficacy of infant recombinant yeast hepatitis B vaccine (Recombinant group) and infant plasma-derived one (Plasma group) in Taiwanese freshers.

METHODS

Recruited were a total of 38 377 freshmen who underwent university entrance health examinations from 2003 to 2015. Subjects were assigned into two groups-plasma type and recombinant type, according to the national neonatal hepatitis B immunization program. The seroprevalences of hepatitis B surface antigen, antibody against hepatitis B surface antigen, and antibody against hepatitis B core antigen in each group and gender were calculated. Multivariate logistic regression analysis was performed to compare the efficacy of two groups.

RESULTS

The HBsAg-positive rates in the plasma group and recombinant group were 1.5% and 0.3% respectively. The anti-HBs positive rates were 43.6% and 30.9%. The hepatitis B viral natural infection rates were 3.6% and 1.3%. Taking those who were born in July 1986-April 1992 as baseline group after adjustment for gender and age at hepatitis B markers checkup time, the efficacy of recombinant group in decreasing HBsAg positive rate, and decreasing hepatitis B virus natural infection rate was 71.0% (95% C.I.: 59.0-79.0%, P<.001) and 65.0% (95% C.I. 58.0-71.0%, P<.001) respectively. On the contrary, the seroprevalence of anti-HBs positive rate in recombinant group was 39.0% (95% C.I.: 36.0-42.0%, P<.001) lower than that of plasma group. (P<.001).

CONCLUSION

Higher disappearance rate of anti-HBs was noted in recombinant group than in plasma group when the subjects reached their youth and young adulthood in Taiwan.

Hepatitis B vaccine and the need for a booster dose after primary vaccination

OBJECTIVES

Protective antibodies levels, induced by Hepatitis B virus (HBV) vaccine, persist for long-term after primary immunization, but there is evidence that, as the time since vaccination increases, there is a reduced ability to maintain immune memory. The study aim was to determine the prevalence and the duration of persistence of an anti-HBs titer with ≥10mIU/mL and eventual predictors of reduced seroprotection.

METHODS

The study was conducted among students attending medical and healthcare professions schools from January 2014 to June 2016. Data were collected through the review of medical records completed during the medical surveillance visit. All subjects had received HBV vaccine according to the Italian Ministry of Health indications.

RESULTS

The results are reported for 722 subjects. Positive anti-HBs titer was found in 72.6% (95% CI=69-76). The mean age of the subjects was 25.5years. Subjects vaccinated during adolescence and students that had received an adult vaccine dose were significantly more likely to be seroprotected. The longer the time interval since vaccination the lower the probability of being seroprotected; however if the role of time since vaccination was considered after stratification by vaccine dose, a statistically significant association with a lower percentage of seroprotected remains only in the subgroup of subjects who received the pediatric dose. The findings of the multivariate regression analysis partially confirmed those of the univariate analysis.

CONCLUSIONS

In conclusion, our findings show that over 25% of HBV vaccine recipients had an antiHBs titer <10mIU/ml after 18years of more from the primary vaccination. Furthermore, in the case a booster dose would be needed, our results suggest that the vaccination strategy should prefer administration of a vaccine adult dose during early adolescence, since it might offer longer-term protection through adulthood.

A Single Center Analysis of the Positivity of Hepatitis B Antibody after Neonatal Vaccination Program in Korea

The antibody to hepatitis B surface antigen (anti-HBs) seropositivity rate after 3 doses of hepatitis B virus (HBV) vaccination during infancy period is known to be higher than 90%. However, a considerable number of vaccines do not form protective anti-HBs or chronologic decrease of anti-HBs. We retrospectively collected data of HBV serologic test results in 20,738 individuals from 2000 to 2015. After exclusion criteria were applied, 19,072 individuals were included. We analyzed the anti-HBs seropositivity rate, anti-HBs disappearance rate, anti-HBs positive seroconversion rate after receiving a booster vaccine, and the difference in anti-HBs positivity between the 2 groups; group A (born before 2005, while both recombinant vaccines and plasma-derived vaccines were used) and group B (born after 2005, when only recombinant vaccines were used by national regulation). The anti-HBs seropositivity rate was 55.8%, but there was a significant difference in the rate of seropositivity for anti-HBs between the group A and B (53.0% vs. 78.1%, P < 0.001). There was no significant age-adjusted difference in the mean seropositivity rate between the 2 groups (P = 0.058). In addition, the anti-HBs positivity rate was significantly lower in the group A as compared with the group B during infancy (83.1% vs. 92.1%, P < 0.001). A total of 1,106 anti-HBs-positive subjects underwent serologic tests more than twice. Of these, 217 subjects (19.6%) showed anti-HBs disappearance. After booster vaccinations, 87.4% (83/95) achieved seroconversion from seronegative to seropositive. Our results highlight the importance of lifelong protection against HBV and the possible necessity of booster vaccination after adolescent period.

Effects of hepatitis B vaccine boosters on anti-HBs-negative children after primary immunization

This study was aimed at evaluating the changes of hepatitis B surface antibody (anti-HBs) titer after booster vaccinations in 5-15-year-old children with negative antibodies (<10 mIU/mL). 225 subjects (mean age, 9.28 ± 2.95 years) included in the study consisted of 123 males and 102 females, with a complete hepatitis B vaccination during infancy. The participants were divided into 3 groups according to their pre-booster anti-HBs level: Group I, <0.1 mIU/mL; Group II, 0.1 to <1.0 mIU/mL; Group III, 1.0 to <10.0 mIU/mL. All the participants were administered 3 doses of booster hepatitis B vaccination (0-1-6 month, 20 µg), and changes in the levels of antibodies were examined at 4 time-points (one month after the first and the third dose, one year and 5 years after the third dose). The seroprotective rate (defined as anti-HBs ≥10.0 mIU/mL) among 225 subjects at the 4 time-points were 93.8%, 100%, 83.6% and 73.4%, respectively (χ² = 90.29, p < 0.05). The seroprotective rate (≥10 mIU/mL) and anti-HBs geometric mean titer (GMT) in Group III were always higher than those in the other 2 groups (all p < 0.05). The immune effect of a 3 -dose booster revaccination is good, and the booster-induced immune response was correlated with the pre-booster titer level, and ≥1.0 mIU/mL ensuring a robust positive response, whereas titers below this value may indicate the need for a course of booster vaccination.

Long-term persistence in protection and response to a hepatitis B vaccine booster among adolescents immunized in infancy in the western region of China

OBJECTIVES

To evaluate the persistence of protection from hepatitis B (HB) vaccination among adolescents immunized with a primary series of HB vaccine as infants, and the immune response to booster doses.

METHODS

Healthy adolescents aged 15-17 y vaccinated with HB vaccine only at birth were enrolled. Baseline serum hepatitis B surface antigen (HBsAg), antibody against hepatitis B surface antigen (anti-HBs) and antibody against hepatitis B core antigen (anti-HBc) were detected by Enzyme-Linked Immunosorbent Assay (ELISA) and anti-HBs level was measured using Chemiluminescent Microparticle Immunoassay (CMIA). The rate of HBV infection was calculated. The seroprotection rate of anti-HBs (≥ 10 mIU/ml) and GMC level were used to evaluate the persistence of immunity from HB vaccination. Those with anti-HBs < 10 mIU/ml were immunized with booster doses of HB vaccine and the anamnestic response was assessed.

RESULTS

Of 180 adolescents who received a primary series of HB vaccinations as infants, 3 (1.7%) had HBV infection and 74 (41.1%) had anti-HBs ≥ 10 mIU/ml with a GMC of 145.11 mIU/ml. The remaining 103 (57.2%) with anti-HBs < 10 mIU/ml received a booster dose of 20 μg HB vaccine and achieved the seroprotection rate of 84% (84/100) and a GMC of 875.19 mIU/ml at one month post-booster. An additional dose of 60 μg HB vaccine was administered to the 16 adolescents with anti-HBs < 10 mIU/ml after the first booster. All of them obtained anti-HBs seroprotection with a GMC of 271.02 mIU/ml at 1.5 months after an additional dose.

CONCLUSIONS

Vaccine-induced immunity persisted for up to 15-17 y in 89.3% (158/177) of participants after a primary HB vaccination in infancy. Administering a booster dose of 20μg HB vaccine elicited an anamnestic immune responses in the majority of individuals with baseline anti-HBs <10 mIU/ml.

Immune responses to hepatitis B immunization 10-18 years after primary vaccination: a population-based cohort study

We evaluated the immune response to neonatal HBV immunization in children of infected parents 10-18 years after primary vaccination. Healthy individuals immunized with an infantile course of three doses of HBV vaccine were tested for persistence of anti-HB surface antibody (HBsAb). Those with an HBsAb level of <10 IU/mL received a booster dose of the vaccine with subsequent doses to those without protective titres. HBsAb concentrations were determined 4 weeks after each dose of the booster vaccine. The data were analysed separately for three age groups: 10-11, 12-14 and 15-18 years old. A total of 541 healthy individuals were studied. The highest seroprotection rate of 48% was observed in the youngest vaccinees (10-11 years old). This declined to 26.5% in the oldest (15-18 years old) group (P = 0.008). The youngest vaccinees showed the highest rate of anamnestic immune responses (96%). However, 25% of oldest individuals failed to mount an anamnestic immune response in challenge with a booster dose of the vaccine (P = 0.005), suggesting waning immunity with increasing age. Age (OR: 0.80; P = 0.01) and prebooster HBsAb levels (OR: 0.37; P = 0.01) identified responders to first booster doses of the vaccine by logistic regression analysis. The majority of high-risk vaccinees showed anamnestic immune response 10-11 years after primary immunization. However, we found a significant proportion (25%) of older individuals with no anamnetic response, which suggests a waning of immune memory. Detailed long-term follow-up studies are necessary to determine the risk of natural infection among these individuals before a booster schedule can be recommended.

Immune response to second vaccination series of hepatitis B virus among booster dose non-responders

OBJECTIVE

To evaluate the response to second vaccination series among post-booster sero-negative children who had previously received compulsory HBV vaccination.

SUBJECTS AND METHODS

After given a booster dose to 1070 children, 103 of them failed to generate anamnestic response (anti-HBs <10 IU/L). Only 91/103 children received additional two doses of recombinant HBV vaccine (i.e. 2(nd) vaccination series) after 1 and 6 months post-booster. Blood sample was withdrawn aseptically one month later for quantitative assessment of anti-HBs to detect development of protective immune response (≥10 IU/L). Immunological vaccination failure was assigned to children who did not develop protective immune response after 2(nd) vaccination series.

RESULTS

Protective immune response was detected among 84/91 children (92.3%). While 7/91 (7.7%) whose age were ≥10 years did not respond and had post-booster undetectable anti-HBs. About 80% of children with post-booster detectable anti-HBs showed significant protective immune response (anti-HBs ≥100 IU/L) and higher GMT (299.1 ± 3.6 IU/L) compared to those with undetectable 60% and 106.2 ± 12.9 IU/L respectively (P<0.05). No significant difference was detected as regards gender or residence, P>0.05. All children with history of rheumatic fever (7 children) or diabetes mellitus (1 child) developed immune response after 2(nd) vaccination series.

CONCLUSION

A booster dose of HB vaccine may be unable to induce sufficient immunological response in children who had undetectable anti-HBs titers. Revaccination for non-responders is an important procedure to increase HBV protection rate.

The one year effects of three doses of hepatitis B vaccine as a booster in anti-HBs-negative children 11-15 years after primary immunization; China, 2009-2011

The aim of this study was to evaluate hepatitis B surface antibody (anti-HBs) levels one year after hepatitis B booster vaccination in anti-HBs-negative (<10 mIU/mL) children 11-15 y after primary vaccination. Anti-HBs titers were examined in 235 children who were negative for hepatitis B surface antigen (HBsAg), anti-HBs, and hepatitis B core antibody (anti-HBc). The children were then divided into 3 groups based on their anti-HBs levels pre-booster: Group I, <0 .1 mIU/mL; Group II, 0.1 to <1 .0 mIU/mL; and Group III, 1.0 to <10 .0 mIU/mL. They were vaccinated with 3 doses of hepatitis B vaccine (0-1-6 month, 20 ug), and anti-HBs levels were measured. One month after the first dose, the anti-HBs positive rates (≥ 10 mIU/mL) in Groups I-III were 56.14%, 83.61% and 100%. One month after the third dose, the anti-HBs-positive rates in Groups I-III were 96.49%, 98.36% and 100%. One year after the third dose, the anti-HBs-positive rates in Groups I-III were 73.68%, 75.41% and 98.29%, respectively. Protective levels declined more rapidly for those with lower titers. Children with pre-booster anti-HBs titers of 1-9.9 mIU/mL might not need any booster dose, and the children with pre-booster titers of 0.1-0.9 and <0 .1 mIU/mL might need more than one dose booster vaccination.

The Serum Anti-HBs Level Among Children Who Received Routine Hepatitis B Vaccination During Infancy in Mianyang City, China: A Cross-Sectional Study

Hepatitis B virus (HBV) prevalence has declined remarkably in children due to nationwide universal vaccination program for HBV in China. However, the persistence of immune response against HBV infection and the optimal time point when a booster vaccination should be performed remain to be elucidated. To assess the persistence and level of antibody against hepatitis B surface antigen (anti-HBs) in a representative population of age 15 and younger who received routine hepatitis B vaccination in Mianyang City, China. A cross-sectional study was conducted in 2011. One thousand five hundred twenty-six children of age 15 and younger who received three doses of 5 μg hepatitis B vaccine series during infancy but did not receive a booster vaccination later were enrolled. Of the 1,526 children, the mean age was 8.2 ± 4.1 and 739 children were male. The median anti-HBs level was 23.0 mIU/mL, and the total percentage of anti-HBs levels ≥10 mIU/mL was 60.9%. With an increase of age, median anti-HBs level, percentage of anti-HBs levels ≥10 mIU/mL, and percentage of anti-HBs levels ≥100 mIU/mL declined remarkably in the early period and reached the lowest level at the age of 3 and then remained relatively stable. The median anti-HBs level, the percentage of anti-HBs levels ≥10 mIU/mL, and the percentage of anti-HBs levels ≥100 mIU/mL in 1- and 2-year-old children were much higher than that in children aged 3-15 (p < 0.05, respectively). Immunity against HBV infection gradually decreased in early ages of children of 15 and younger who received three doses of 5 μg hepatitis B vaccine series during infancy in China. Three dosages of 10 μg hepatitis B vaccine for infants and repeated vaccination or additional booster vaccination for some children at or before age 3 should be provided to get much more powerful immunity to HBV.

The long-term efficacy, 13-23 years, of a plasma-derived hepatitis B vaccine in highly endemic areas in China

OBJECTIVE

To evaluate the long-term effectiveness of the plasma-derived hepatitis B vaccine that has been applied widely in five areas of China where HBV prevalence was highly endemic.

METHOD

A cross-sectional investigation was conducted in 2009 at five HBV surveillance sites around China. The target study subjects of 6772 were born between 1986 and 1996 and received plasma-derived HBV vaccine. Serum samples were collected to test for HBV markers using the microparticle enzyme immunoassay.

RESULTS

The number of participants enrolled was 6772. The average hepatitis B surface antigen (HBsAg) prevalence was 2.01%. The birth dose group included 5052 children. In this group, the average positive rates of HBsAg and hepatitis B core antibody (anti-HBc) were 1.58% and 6.39%, respectively, and these values declined gradually from 1986 to 1996. The positive rates of anti-hepatitis B surface antibody (HBs) and the geometric mean concentration (GMC) of anti-HBs-positive subjects were 41.69% and 115.8mIU/ml.

CONCLUSION

The long-term effectiveness of the plasma-derived hepatitis B vaccine still provided protection 13-23 years after vaccination. It seems that a booster dose is not necessary. Enhancing the rate of the birth dose within 24h is one of the most important measures to prevent and control HBV infection.

The long-term efficacy of Chinese hamster ovary cell derived hepatitis B vaccine after being used for 14-16 years in Chinese rural communities

OBJECTIVE

To evaluate the long-term efficacy of Chinese hamster ovary (CHO) cell derived hepatitis B vaccine after being used for 14-16 years in country community in Hebei province in China.

METHOD

A cross-sectional investigation was carried out in 3 of 7 randomly selected rural communities in Zhengding County in 2013. The children who were born between 1997 and 1999 and were vaccinated with three doses of CHO-derived hepatitis B vaccine were eligible to participate in the study. Their sera samples were tested for HBV serological markers. For HBsAg positive children, their historical results were compared, in order to see whether these were new infections.

RESULTS

Among the 920 participating children, the prevalence of HBsAg, anti-HBs and anti-HBc were 0.65%, 73.15% and 1.20% respectively. The differences between birth-year groups were not significant. When compared with baseline, the vaccine efficacy was 94.2% and the anti-HBs titers of 668 children with sole anti-HBs positivity were 178.8 mI U/ml. By comparing with historical data, no new infection was found in this latest survey. Among 6 mothers of HBsAg positive children, 4 were HBsAg positive, 1 was negative and 1 was unknown.

CONCLUSION

The long-term efficacy of the CHO derived hepatitis vaccine is good and stable for 14-16 years after vaccination. A booster dose seems not necessary. Implementing mother-newborn blocking measures for newborns from HBsAg carrier mothers is urgently needed in the future.

Duration of protection after infant hepatitis B vaccination series

BACKGROUND

Little is known about duration of protection after the infant primary series of hepatitis B (HB) vaccine in settings of low HB endemicity. This study sought to determine the proportion of adolescents immunized as infants who had protective titers of antibody to hepatitis B surface antigen (anti-HBs) before and after a challenge dose of vaccine.

METHODS

US-born 16- through 19-year-olds who received a recombinant HB vaccine 3-dose series initiated within 7 days of birth (group 1) or at ≥4 weeks of age (group 2) and completed by 12 months of age were enrolled. Participants had serologic testing before and 2 weeks after randomization to receive a challenge dose of 10 µg or 20 µg of Engerix-B. Baseline and postchallenge levels of anti-HBs were compared by group, challenge dosage, and demographic and behavioral characteristics.

RESULTS

At baseline, 24% had protective anti-HBs levels of ≥10 IU/mL; 92% achieved protective levels after challenge dose. Although group 1 had a lower proportion of seroprotection at baseline, group and challenge dosage were not associated with postchallenge proportion of seroprotection. Being in group 2, higher test dosage, higher baseline geometric mean titer, and nonwhite race were associated with significantly higher geometric mean titer after challenge dose.

CONCLUSIONS

More than 90% of study participants immunized against HB as infants exhibited a seroprotective response to a challenge dose of vaccine. Duration of protection from the primary infant HB vaccine series extended through the adolescent years in the setting of low HB endemicity.

Seroprevalence of hepatitis B and immune response to hepatitis B vaccination in Chinese college students mainly from the rural areas of western China and born before HBV vaccination integrated into expanded program of immunization

The prevalence of hepatitis B surface antigen (HBsAg) in a population aged 15 y or older was high in China, but an immunization strategy for this population was unavailable. We investigated the seroprevalence of hepatitis B and immune response to HBV vaccine in Chinese college students (n=2040 participants), 11.1%, 80.8%, and 8.1% had confirmed, unknown and no HBV vaccination history, respectively. The seropositive rates for HBsAg, anti-HBs sole and anti-HBs plus anti-HBc were 12.6%, 25.7%, and 30.1%, respectively. The HBsAg seropositive rate was significantly lower in participants with confirmed HBV vaccination history than in those with unknown or no vaccination history (5.3%, 13.6%, and 12.6%, respectively, P=0.0019). The anti-HBs alone seropositive rate was significantly higher in participants with confirmed HBV vaccination history than in those with unknown or no vaccination history (37.6%, 25.3%, and 13.8%, respectively, P<0.0001). Participants negative for HBsAg, anti-HBs, and anti-HBc at baseline (n=600) were given three doses of recombinant HBV vaccine (GlaxoSmithKline) at month 0, 1, and 6. Robust immune response was elicited after two and three doses (seroprotective rate: 91.9% and 99.0%, respectively, and geometric mean concentration [GMC]: 95.8 and 742.6 IU/L, respectively). Fourteen months after the third dose, the anti-HBs seroprotective rate of the group remained more than 97%. The seroprotective rates and GMCs did not differ significantly by vaccination history. This study suggested that three doses of 20 μg HBV vaccine were needed for college students negative for HBsAg, anti-HBs, and anti-HBc to ensure high seroprotective rates and concentrations.

Efficacy of hepatitis B vaccine boosters among neonatally vaccinated university freshmen in Taiwan

BACKGROUND & AIMS

Long-term protection against hepatitis B virus (HBV) after vaccination remains widely debated. We evaluated the efficacy of a modified 3-dose booster protocol in neonatally vaccinated university students in Taiwan.

METHODS

Changes in the levels of antibodies to the hepatitis B surface antigen (anti-HBs) were examined in 250 university students over a 3-year period. Group A (n=39) lacked seroprotective levels of anti-HBs, and declined to receive a booster dose of the HBV vaccine. Group B (n=128) lacked seroprotective levels of anti-HBs, and received booster doses of the HBV vaccine according to a modified 3-dose booster protocol. Group C (n=83) possessed seroprotective levels of anti-HBs, and did not receive a booster dose.

RESULTS

The levels of seroprotective anti-HBs increased in 12.8% of Group A and 14.5% of Group C, suggesting that our entire cohort had experienced booster effects from natural HBV exposure. However, no new HBV infections were observed, and 53.9% of Group B maintained protective levels of anti-HBs during the follow-up period.

CONCLUSIONS

The use of the modified 3-dose booster protocol induced significant long-term increases in the titer of anti-HBs in over 50% of the neonatally vaccinated participants with previously non-protective titers. However, in the absence of a vaccine booster, some neonatally vaccinated people with low anti-HBs titers may nonetheless produce anamnestic responses to HBV upon exposure, suggesting that protection from neonatal vaccination may persist, despite low titers of anti-HBs.

Determinants of Long-term protection after hepatitis B vaccination in infancy: a meta-analysis

BACKGROUND

The duration of protection after hepatitis B vaccination in early infancy is unclear and may be related to vaccination schedule, dosage, vaccine type and population characteristics. Factors potentially influencing waning immunity were assessed.

METHODS

A systematic review was performed. The main outcomes were prevalence of anti-hepatits B antibodies ≥ 10 mIU/mL after primary or booster vaccination. Factors potentially influencing protection were assessed in an adjusted random-effects meta-analysis model by age for both outcomes. Results of both meta-analyses were combined in a prognostic model.

RESULTS

Forty-six studies reporting on the anti-hepatits B antibodies ≥ 10 mIU/mL 5 to 20 years after primary immunization and 29 on booster response were identified. The adjusted meta-analyses identified maternal carrier status (odds ratio [OR]: 2.37 [1.11; 5.08]), lower vaccine dosage than presently recommended (OR: 0.14 [0.06; 0.30]) and gap time between last and preceding dose of the primary vaccine series (OR: 0.44 [0.22; 0.86]) as determinants for persistence of anti-hepatits B antibodies ≥ 10. A lower vaccine dosage was also associated with failure to respond to booster (OR: 0.20 [0.10; 0.38]). The prognostic model predicted long-term protection of 90% [77%; 100%] at the age of 17 years for offspring of noncarrier mothers vaccinated with a presently recommended dose and vaccination schedule.

CONCLUSIONS

Based on meta-analyses, predictors of waning immunity after hepatitis B vaccination in infancy could be identified. A prognostic model for long-term protection after hepatitis B vaccination in infancy was developed.

Hepatitis B vaccination: a completed schedule enough to control HBV lifelong? Milan, Italy, 17-18 November 2011

The Viral Hepatitis Prevention Board (VHPB) organized an international meeting in Milan in November 2011 on the question of whether completing a course of hepatitis B vaccination confers lifelong protection against hepatitis B virus infection and its complications. Presentations covered vaccine efficacy including factors influencing long-term protection; breakthrough infections; the immunological effect of natural boosting; the effectiveness of universal hepatitis B vaccination in different countries, and issues relating to national, regional and global policies on booster vaccination. Findings from four continents were presented at the meeting, with data now extending to follow-up for nearly 30 years after full primary vaccination. The results reported add to the extensive and growing body of knowledge, demonstrating that in spite of subsequent decline and ultimate loss of detectable serum anti-HBs, a full primary course of hepatitis B vaccine confers complete protection against acute clinical disease and chronic hepatitis B infection for long periods of time. Our understanding of the role and functions of T and B cells in protective immunity deepens, although the picture is still complex. A framework for future work in several areas emerged from the meeting, including monitoring and surveillance of vaccination programmes, breakthrough infections, hepatitis B in immigrant populations, and vaccine-escape viral mutants. One further concrete recommendation is the setting up of a working group to standardize definitions on terms such as "immunity", "protection", "immune memory", "non-responders", "long-term", "anamnestic response", "breakthrough" and "vaccine failure".

Increased seroprevalence of HBV DNA with mutations in the s gene among individuals greater than 18 years old after complete vaccination

BACKGROUND & AIMS

Despite the success of a universal vaccination program against hepatitis B virus (HBV) in Taiwan, a small but substantial proportion of individuals remain infected by mutant viruses that escape the vaccine. We investigated the seroepidemiology and genotypic characteristic of HBV for long periods after neonatal vaccination.

METHODS

We measured hepatitis B surface antigen (HBsAg), antibody to hepatitis B core antigen (anti-HBc), and antibody to hepatitis B surface antigen (anti-HBs) in 1214 serum samples collected throughout Taiwan from individuals 0.6-87.8 years old in 2007. HBV DNA was detected using polymerase chain reaction and sequence analysis in vaccine recipients who tested positive for anti-HBc and/or HBsAg.

RESULTS

The overall seroprevalence of HBsAg and anti-HBc was significantly lower among individuals born after the initiation of the nationwide vaccination program (P < .001). However, we observed increasing seroprevalence of anti-HBc and isolated anti-HBs when subjects were grouped by age: at 10-14, 14-18, to 18-21 years of age, values were 0.4%, 1.9%, and 8.1% (P = .0135) and 43.7%, 55.4%, and 59.6% (P = .0093), respectively (χ(2) test for trend). A large increase was observed in the percentage of patients who tested positive for HBV DNA at 18-21 years of age (3.0% vs 0.2% [P = .002] for all eligible subjects and 5.7% vs 0.3% [P < .001] for subjects vaccinated with ≥3 doses). Five of 8 completely vaccinated individuals who were seropositive for HBV DNA carried variants with mutations in the S gene.

CONCLUSIONS

Universal vaccination effectively controls HBV infection in children and adolescents. However, after adolescence, there is a significant increase in the seroprevalence of anti-HBs, anti-HBc, and HBV DNA, indicating that new preventative strategies are needed for adults.

Persistence of long-term immunity to hepatitis B among adolescents immunized at birth

The long-term duration of recombinant hepatitis B vaccine-induced immunity among persons vaccinated starting at birth is still not well understood. Waning of vaccine-induced immunity could leave young adults at risk of hepatitis B virus infection due to behavioral or occupational exposures. We followed a cohort of children immunized starting at birth with a 3-dose regimen of recombinant hepatitis B vaccine (5 mcg, 2.5 mcg, 2.5 mcg). They were challenged with a booster dose of the hepatitis B vaccine 10 and 15 years after vaccination to assess anamnestic response as a measure of persistence of protection. Among 108 participants who had lost protective antibody levels against hepatitis B, the majority (>70%) had an anamnestic response to the booster dose; response rates did not decline significantly between 10 and 15 years follow-up periods. A high antibody concentration following primary vaccination was independently associated with an anamnestic response later on in life. Nonetheless, ~20-30% of participants were unable to mount an immune response after boosting. Hepatitis B revaccination might be required for persons vaccinated starting at birth if opportunities for hepatitis B virus exposure exist. Future vaccine recommendations should be based on studies ascertaining protection against clinically significant disease.

Waning immunity and booster responses in nursing and medical technology students who had received plasma-derived or recombinant hepatitis B vaccine during infancy

BACKGROUND

The national hepatitis B virus (HBV) vaccination program was launched in Taiwan in 1984. After November 1992, a recombinant HBV vaccine replaced the plasma-derived HBV vaccine.

METHODS

A total of 1,812 nursing and medical technology freshman students was tested to evaluate their waning immunity toward hepatitis B. In the 2007 (2008) academic year, 438 (382) students testing nonprotective antibodies received 3 (1) booster doses of HBV vaccine according to suggestions from Taiwan's Center for Disease Control (CDC).

RESULTS

The seroprevalences of hepatitis B surface antigen (+) were 0.8% and 0.7% in the plasma-derived and recombinant group, respectively; for antibody to hepatitis B surface antigen (anti-HBs) (+), they were 43.2% and 33.3% (P < .001), respectively. In the 2007 freshman group, 99.1% of the students previously vaccinated with plasma-derived HBV vaccine exhibited anti-HBs seroconversion. In the 2008 freshman group, the booster dose induced anti-HBs seroconversions of 92.1% and 95.9% in the students who had received the plasma-derived and recombinant HBV vaccine, respectively (P = .370).

CONCLUSION

Most students exhibited signs of immune memory after receiving the booster, regardless of having received plasma-derived or recombinant HBV. Only a small number of vaccinees lost their immune memory after 16 years, suggesting that some students might benefit from boosting before proceeding to clinical practice.

Evidence of protection against clinical and chronic hepatitis B infection 20 years after infant vaccination in a high endemicity region

Vaccination against hepatitis B virus (HBV) immediately after birth prevents neonatal infection by vertical transmission from HBV carrier mothers. There is an ongoing debate whether infant vaccination is sufficient to protect against infection when exposed to HBV later in life. We studied 222 Thai infants born to HBsAg -/+ and HBeAg -/+ mothers who were vaccinated with recombinant hepatitis B vaccine at 0-1-2-12 months of age. A subset of 100 subjects received a booster dose at age 5 years. Blood samples collected yearly for 20 years were examined for anti-HBs antibodies and serological markers of hepatitis B infection (anti-HBc, HBsAg, and in selected cases HBeAg, anti-HBe, HBV DNA). During the 20-year follow-up, no subject acquired new chronic HBV infection or clinical hepatitis B disease. During the first decade, possible subclinical breakthrough HBV infection (anti-HBc seroconversion) was only observed in subjects born to HBsAg +/HBeAg + mothers (6/49 [12.2%]). During the second decade, breakthrough HBV infections were detected in all groups (18/140 [12.8%]). Increases in anti-HBs concentrations that were unrelated to additional HBV vaccination or infection were detected in approximately 10% of subjects in each decade. Primary infant vaccination with a recombinant hepatitis B vaccine confers long-term protection against clinical disease and new chronic hepatitis B infection despite confirmed hepatitis B exposure.

Hepatitis B virus infection, its sequelae, and prevention by vaccination

Hepatitis B virus (HBV) infection is a global health problem. There are >350 million of people chronically infected with this virus worldwide. Hepatitis B vaccines are effective in preventing the infection. Humoral immunity is the key factor in conferring the protection. Hepatitis B surface antibody titers of ≥10mIU/mL are protective. Chronic carriage of HBV is related to the age when the infection occurs, the younger the age the higher the chronicity rate. Hence, vaccination should be given in early childhood. People vaccinated in infancy have a protection of >20 years, and hepatocellular carcinoma decreases in them. Although the vaccine-conferred immunity wanes by time, a universal booster is not recommended at present.

Serologic and molecular characteristics of hepatitis B virus among school children in East Java, Indonesia

Universal childhood hepatitis B vaccination was introduced in Indonesia in 1997; by 2008, coverage was estimated to be 78%. This study aimed to investigate the serologic status and virologic characteristics of hepatitis B virus (HBV) among the children in East Java. A total of 229 healthy children born during 1994-1999 were enrolled in this study. Overall, 3.1% were positive for hepatitis B surface antigen (HBsAg) and 23.6% were positive for antibody to HBsAg (anti-HBs). HBV DNA was detected in 5 of 222 HBsAg-negative carriers, which were suggested to be cases of occult HBV infection. A single amino substitution (T126I) in the S region was frequently found. HBV infection remains endemic, and the prevalence of anti-HBs remains insufficient among children in East Java, Indonesia.

Determination of immune memory to hepatitis B vaccination through early booster response in college students

The long-term protection of hepatitis B (HB) vaccination has been debated for years. The purpose here was to evaluate the kinetic changes of antibody to HB surface antigen (anti-HBs) and define immune memory of the HB vaccine among college students who had previously received full neonatal immunization against HB. In all, 127 college students aged 18-23 years born after July 1984 who had completed HB vaccination and were seronegative for all three HB viral markers, including HB surface antigen (HBsAg), antibody to HB core protein (anti-HBc), and anti-HBs, were recruited. They received three doses of HB vaccine at enrollment, 1 month and 6 months after enrollment. Their anti-HBs titers were assayed at enrollment, 7-10 days, 1 month, 6 months, and 7 months following the first dose of HB vaccine. The anti-HBs seroprotective rates for subjects 7-10 days, 1 month, 6 months, and 7 months postvaccination were 20.5%, 75.6%, 94.5%, and 99.2%, respectively. Those who were seroprotective at 7 to 10 days after one dose of HB vaccine booster developed significantly higher levels of anti-HBs at 1 and 6 months than those not developing seroprotective anti-HBs response at an earlier timepoint.

CONCLUSION

At least one-quarter of HB vaccinees have lost their immune memory to the HB vaccine when entering college. Immune memory to HB vaccine was identified by early seroconversion, which was present in only 20% of vaccinees in the present study. To ensure higher than 90% anti-HBs seroconversion rates, at least 2 doses of HB booster vaccines are recommended for at-risk youths who received complete HB vaccinations in neonatal or infant periods but are seronegative for HBsAg, anti-HBs, and anti-HBc in adolescence.