Response to booster doses of hepatitis B vaccine among young adults who had received neonatal vaccination

Hepatitis B virus immunity prior to and after administration of a ‘booster’ dose of vaccine among health-care students at a South African university

Background

Health-care students (HCSs) are at risk of occupational exposure to hepatitis B virus (HBV) infection despite an effective hepatitis B vaccine (HepB) being available. The majority of current HCSs are born after HepB was introduced into the South African Expanded Programme on Immunisation in 1995. Thus, it is assumed that having received HepB in infancy, a single 'booster' dose would suffice. This study aimed to investigate HBV immunity prior to and after administration of a HepB 'booster' dose.

Methods

Hepatitis B surface antibody (anti-HBs) levels were determined in first year HCSs at the University of the Witwatersrand, before and after receiving the 'booster'. Participant demographics and HepB history were captured using a structured questionnaire.

Results

Before receiving the 'booster', 56% (101/180) had anti-HBs < 10 mIU/mL and were non-immune. A further 35% had anti-HBs levels of 10 - 99 mIU/mL, and 9% had ≥100 mIU/mL. <30% of HCSs self-reported completion of a three-dose primary series, which was significantly associated with higher baseline anti-HBs levels compared to those with a partial schedule (p = 0.045). Following vaccination, 39% (71/180) returned for follow-up with a significant median (IQR) increase of 476 (151 - 966) mIU/mL (p < 0.001). Of the 45 students who had non-immune baseline levels, 73% (33/45) responded with ≥100 mIU/mL, 16% (7/45) with 10 - 99 mIU/mL and 11% (5/45) remained non-immune. Levels of ≥100 mIU/mL were achieved by 100% of students with baseline levels ≥10 mIU/mL (n = 26).

Conclusion

More than half of the HCSs were not immune to HBV prior to receiving the recommended 'booster' vaccine. Following vaccination, 7% (5/71) remained unprotected. This study highlights that in the absence of vaccination records and without confirming the immune status of HCSs, it cannot be assumed that HCSs will be protected following a 'booster'. Policy reform and inclusion of serological tests for immunity prior to HCSs initiating clinical exposure are recommended.

Long-Term Effectiveness of Hepatitis B Vaccination in the Protection of Healthcare Students in Highly Developed Countries: A Systematic Review and Meta-Analysis

Hepatitis B virus represents an important global health problem. In highly developed countries, mass vaccination campaigns of newborns in recent decades have drastically reduced the proportion of carriers. However, workers exposed to blood and body fluids, including healthcare students, can be at risk of exposure. In order to assess the proportion of susceptible individuals in the specific population of healthcare students in highly developed countries, a systematic review and meta-analysis was performed to summarize the evidence on the persistence of humoral immune protection induced by the primary cycle of hepatitis B vaccination, as well as the proportion of true non-responders. Forty-six studies were included in the final analysis (52,749 participants). Overall, the seroprotection prevalence at the pre-exposure assessment was equal to 73.8% (95% CI 69.1-78.0); the prevalence of anamnestic response following the administration of a challenge dose was 90.9% (95% CI 87.7-93.3), demonstrating a high proportion of persistence of vaccination-induced immunity. Among those without evidence of anamnestic response, 5.0% (95% CI 2.1-11.5) were non-responders following the completion of a secondary immunization cycle. These findings demonstrate that the majority of healthcare students vaccinated with the complete HBV primary cycle maintain an effective humoral immunity against this pathogen for over two decades.

The impact of different IPV-OPV sequential immunization programs on hepatitis A and hepatitis B vaccine efficacy

In recent years, the Global Polio Eradication Initiative has gradually implemented a global shift in polio immunization programs. Few studies cover polio immunization program impacts on the efficacy of other vaccines. This study investigated whether polio immunization programs affected hepatitis A (HepA) and hepatitis B (HepB) vaccination efficacy. Serum samples were collected from 968 infants before the first dose of polio vaccine, 28 days after completing primary polio immunization, and at 24 months old. Infants were classified into six polio immunization program groups: 1sIPV+2bOPV, 2sIPV+1bOPV, 2sIPV+1tOPV, 1cIPV+2bOPV, 2cIPV+1bOPV, and 2cIPV+1tOPV (sIPV: Sabin inactivated poliovirus vaccine; cIPV: Salk inactivated poliovirus vaccine; b, bivalent; t, trivalent; OPV, oral polio vaccine). No significant differences existed in antibody titers against HepA virus (anti-HAV) among the polio immunization program groups at any of the three time points (pre-first dose [p = 0.412], 28 days after primary immunization [p = 0.676], 24 months old [p = 0.556]). Before the first dose (p = 0.178) and at age 24 months (p = 0.987), no significant differences existed in HepB surface antibody (HBsAb) titers between the six polio immunization program groups). Twenty-eight days after primary immunization, no significant difference existed in HBsAb titers between groups after Bonferroni correction. Following HepA and HepB immunization, anti-HAV and HBsAb positivity reached > 98% in all groups, reflecting effective immunization. Our data suggest that different polio immunization programs did not affect HepA and HepB vaccine efficacy; HepA and HepB vaccines maintained high effectiveness irrespective of polio immunization program. This trial was registered on Clinical Trials.gov: NCT03614702.

Increasing hepatitis B vaccination coverage of healthcare workers - global lessons for South Africa

Healthcare workers (HCWs) are at high risk of contracting hepatitis B (HB), a severe blood-borne vaccine-preventable disease, caused by HB virus (HBV) infection. Low HB vaccine (HepB) coverage has resulted in suboptimal protection and high HBV infection rates in South African HCWs. Studies from Africa have identified cost; unavailability/lack of access to HepB; and lack of awareness/knowledge of HB and HepB, as barriers to HCW uptake. Studies from Europe show little difference in HepB coverage between countries mandating versus recommending HepB. Providing easy and sustained access to free HepB to student HCWs, together with education about HB and HepB, are recommended to create demand for HepB. Only if this fails should mandatory vaccination be considered.

Hepatitis B surface antigen and antibody positivity among women of childbearing age after three decades of universal vaccination in South Korea

OBJECTIVES

We estimated the impact of universal hepatitis B immunization using 18-year data of women who are of childbearing age in South Korea.

METHODS

We used hepatitis B surface antigen (HBsAg) and antibody (anti-HBs) data of 145,993 women aged 20-49 years during 2001-2018 at the Gangnam CHA Medical Center. Annual prevalences of HBsAg and anti-HBs positivity were calculated and tested for linear trend. We conducted age-period-cohort (APC) analysis to obtain period and cohort effect.

RESULTS

Overall proportion of HBsAg positivity was 3.5% (n = 5050) and anti-HBs positivity was 75.3% (n = 109,907) during the study period. HBsAg positivity percentage decreased from 5.1% in 2001 to 2.5% in 2018 (P < 0.001) while anti-HBs positivity increased from 59.9% to 75.8% (P = 0.002). Average annual percent change of HBsAg positivity was -5.9% (95% confidence interval (CI): -6.9%, -4.8%). The period and cohort RR curve identified a consistent decrease in HBsAg positivity over time and across generations.

CONCLUSIONS

We observed a concurrent decrease in HBsAg and an increase in anti-HBs seropositivity among Korean women of childbearing age, implicating success in preventing vertical transmission.

Is it the Right Time to Introduce the Hepatitis B Booster Vaccine in National Immunization Schedule? An Analysis from the Available Evidence

Hepatitis B virus (HBV) infection is a global health concern, and it is considered one of the deadliest infections in the world, having nearly 1.2 million deaths annually. Around 75% of all global HBV carriers live in the Asia-Pacific region. In this regard, India has a prevalence ranging between 2% and 7% with exposure rates of 10%–60%. Hepatitis B is a vaccine-preventable disease. In India, the World Health Organization protocol for hepatitis B vaccination has been followed, and it is given free of cost in public health facilities under the National Immunization Schedule. Despite the free hepatitis vaccination program in India, coverage and awareness are low. Low awareness, followed by low coverage of hepatitis vaccination, can prove dangerous for the Indian population in the long run. A majority of chronic hepatitis cases progress silently to end-stage liver disease without having many signs and symptoms. Once occurred, a complete cure is not possible with currently available drugs. The studies from neighboring countries such as China and Taiwan documented that the impact of single-dose booster for children of 10 years has made a significant difference from the cost-effectiveness perspective. They have also included the booster dose in their national vaccination program. Considering the low level of vaccination awareness, small coverage, high disease burden, and high treatment cost, now, it is high time for India to introduce hepatitis B booster vaccine.

Discordance of hepatitis B vaccination policies for healthcare workers between the USA, the UK, and Germany

The hepatitis B (HB) vaccine is effective for the prevention of HB virus infection. It has been widely accepted that an anti-HB surface antibody (HBs) level ≥10 mIU/mL is protective against HB virus infection. Although transient infection can occur in individuals who attain a peak level of anti-HBs ≥10 mIU/mL after primary vaccination, long-term follow-up studies show that successful primary vaccination can prevent individuals from acute clinical hepatitis and chronic infection. Healthcare workers (HCWs) are at-risk individuals. Based on the accumulated data, the USA considers an anti-HBs level ≥10 mIU/mL to constitute successful vaccination for HCWs. In contrast, because some anti-HBs assays cannot accurately measure in the low anti-HBs range, including 10 mIU/mL, the UK and Germany consider an anti-HBs level ≥100 mIU/mL to constitute successful vaccination for HCWs. In the USA and UK, a booster dose is unnecessary for HCWs after successful vaccination. In Germany, anti-HBs testing is recommended for HCWs who are at particularly high individual exposure risk 10 years after successful primary immunization, and a booster dose is offered if the anti-HBs level has declined to ˂100 mIU/mL. The differences in the goal of HB vaccination, reliability of anti-HBs assays, and use of booster vaccination cause discordance in HB vaccination policies for HCWs.

Long-term follow-up of a vaccination program for infants born to HBsAg-positive mothers in Stockholm County, Sweden

We investigated the long-term antibody response to hepatitis B virus (HBV) vaccination in babies born to chronically infected mothers. They received one dose of monovalent HBV vaccination at birth and one month of age, followed by 3 doses of hexavalent vaccine including an HBV component at ages 3, 5, and 12 months, respectively, with a very high percentage of protective anti-HBs levels at 13 months. At the age of 8-12 years, 56 out of 68 children (82%) had protective levels of anti-HBs, two had signs of anti-HBc seroconversion without any history of clinical disease and none had ongoing infection. A small subgroup was retested after one booster dose, in all resulting in increase in anti-HBs from below 10 IU/L to levels corresponding to protective immunity. We conclude that this vaccination strategy is effective throughout the first decade of life in avoiding chronic infection and in maintaining a good serological response.

Hepatitis B Surface Antibody Titers at One and Two Years after Hepatitis B Virus Vaccination in Healthy Young Japanese Adults

Objective Since healthcare providers face an increased risk of hepatitis B virus (HBV) infection because of their work, vaccination plays a critical role in preventing HBV transmission. However, the duration for which acquired HBV surface antibodies (anti-HBs) persist remains unknown. To evaluate the primary immunologic response to HBV vaccination and its persistence in healthy Japanese adolescents. Methods In total, 690 young adults underwent HBV vaccination with a three-dose schedule. The primary response was determined by the anti-HBs titers at 1-2 months after the final dosage. Subjects with anti-HBs titers of <10, 10-100, and >100 mIU/mL were classified as "non-responders," "low-responders," and "sufficient responders," respectively. Anti-HB titers were re-measured at 1 or 2 years after vaccination. Results First, 95.8% and 72.8% of the subjects had anti-HBs titers of >10 and >100 mIU/mL, respectively, as a primary response. The anti-HBs titers measured at 1 and 2 years after vaccination were significantly correlated with those of the primary response (1 year: r=0.893, p<0.0001; 2 years: r=0.902, p<0.001). Most subjects with a titer of >100 mIU/mL at the primary response maintained an anti-HBs titer of >10 mIU/mL [1 year after vaccination, 208/209 (99.5%); 2 years after vaccination, 72/81 (90.1%)]. However, in subjects with a primary response of 10-100 mIU/mL the anti-HBs titer frequently declined; 17/38 (44.7%) and 9/10 (90.0%) subjects had a titer of <10 mIU/mL at 1 and 2 years, respectively. Conclusion The primary response was associated with the anti-HBs titers at 1 and 2 years after vaccination, and the anti-HBs titers of 54.2% of the low responders were not maintained for 2 years, even if they were vaccinated as healthy young adults.

Long-term immunogenicity of hepatitis B vaccine and impact of a booster dose on health care

Background: Accidental exposure to sharp instruments is an important problem for health care students. Thus, the aim of this study was to determine the rate of immunity in health care students 2 decades after national neonatal hepatitis B (HB) vaccination.

Methods: All junior students attending medicine, nursing and midwifery schools were screened for anti-HBs. One dose of hepatitis B vaccine was offered to all participants who did not have antibodies to HB surface antigen (anti-HBs) of > 10 IU/L; then, they were tested for anti-HBs after a month. The participants were classified into 3 groups: postboosting nonimmune, postboosting immune, and preboosting immune. Chi square test and ANOVA were used for data analysis.

Results: In the first step, 65.20% of participants did not show immunity, but after receiving a booster dose, only 6.0% remained nonimmune. The mean age of nonimmune students was significantly higher than that of students who had postboosting immune and preboosting immune status (p=0.001 and 0.002, respectively). Also, the mean injection time from last shot was higher in postboosting immune group compared to preboosting immune group (p<0.001). Also, prebooster anti-HBs level was significantly different among participants with suboptimal response and those who developed anamnestic response, indicating preserved immune memory (p=0.001).

Conclusion: High anamnestic response to HBV booster dose indicates sufficient immunity to HBV in the majority of health care students. However, identifying students who cannot respond to a booster dose of vaccine seems to be necessary at the beginning of health care courses.

Transcriptome profiling in blood before and after hepatitis B vaccination shows significant differences in gene expression between responders and non-responders

INTRODUCTION

As the hepatitis B virus is widely spread and responsible for considerable morbidity and mortality, WHO recommends vaccination from infancy to reduce acute infection and chronic carriers. However, current subunit vaccines are not 100% efficacious and leave 5-10% of recipients unprotected.

METHODS

To evaluate immune responses after Engerix-B vaccination, we determined, using mRNA-sequencing, whole blood early gene expression signatures before, at day 3 and day 7 after the first dose and correlated this with the resulting antibody titer after two vaccine doses.

RESULTS

Our results indicate that immune related genes are differentially expressed in responders mostly at day 3 and in non-responders mostly at day 7. The most remarkable difference between responders and non-responders were the differentially expressed genes before vaccination. The granulin precursor gene (GRN) was significantly downregulated in responders while upregulated in non-responders at day 0. Furthermore, absolute granulocytes numbers were significantly higher in non-responders at day 0.

CONCLUSION

The non-responders already showed an activated state of the immune system before vaccination. Furthermore, after vaccination, they exhibited a delayed and partial immune response in comparison to the responders. Our data may indicate that the baseline and untriggered immune system can influence the response upon hepatitis B vaccination.

Mother-to-child transmission of hepatitis B: Examining viral cut-offs, maternal HBsAg serology and infant testing

BACKGROUND & AIMS

Antipartum antiviral therapy in the setting of high viral load is recommended to prevent mother-to-child transmission of hepatitis B although recommended viral load cut-offs vary. Quantitative HBsAg has been proposed as an alternative screening strategy to identify high viral load in this setting. Guidelines suggest testing all infants for vaccine response and infection. We set out to re-examine viral load cut-offs; the predictive value of quantitative HBsAg and the need for follow-up infant testing in our cohort.

METHODS

A retrospective cohort study of 469 HBsAg positive mother-baby pairs from 2 tertiary hospitals in Sydney was performed. Antiviral therapy (lamivudine or tenofovir disoproxil fumarate) was offered to women with viral load ≥6 log₁₀  IU/mL (high) from 32 weeks gestation. Transmission and vaccine response was analysed according to viral load. The utility of quantitative HBsAg in identifying high viral load was examined.

RESULTS

Mother-to-child transmission only occurred in setting of high viral load, in 0.85% (1/117) of those who received antiviral therapy and in 8.66% (2/23) of those who chose not to. Quantitative HBsAg did not accurately identify high-risk mothers HBV DNA ≥6 log₁₀  IU/mL. Successful infant vaccine response was 98.7% overall, and 99.4% when viral load was <6 log₁₀  IU/mL.

CONCLUSION

Antiviral therapy initiated at 32 weeks when maternal viral load is ≥6 log₁₀  IU/mL almost completely abrogates transmission. Quantitative HBsAg does not reliably predict high viral load. When maternal viral load is <6 log₁₀  IU/mL, high vaccine efficacy and zero transmission suggests testing infants is of little value.

Three decades of neonatal vaccination has greatly reduced antenatal prevalence of hepatitis B virus infection among gravidae covered by the program

OBJECTIVES

To evaluate the impact of three decades of hepatitis B vaccination in infancy on antenatal prevalence of hepatitis B surface antigen (HBsAg) carriage in 93,134 Hong-Kong born gravidae managed in 1997-2015.

METHODS

Annual prevalence of HBsAg carriage on routine antenatal screening was examined with respect to maternal year of birth in three periods i.e. pre-1983 (before availability of vaccination), 1983-1988 (vaccination of infants born to HBsAg-carriers), and after 1988 (universal vaccination).

RESULTS

Overall HBsAg carriage was 8.3% (7737/93,134), decreasing from 10.5% in 1997 to 6.5% in 2015 (p < 0.001), and from 8.8%, 7.0% to 3.1%, respectively, for the three period-of-birth cohorts (p < 0.001). Annual prevalence decreased from 9.9% in 1997 to 7.5% in 2015 (p < 0.001) in the pre-1983 cohort, but showed neither difference nor trend in the other two cohorts. However, the annual prevalence showed significantly falling trends from the pre-1983 to the post-1988 cohorts for the years 2007-2008 and 2010-2015.

CONCLUSIONS

A progressive decline in overall annual prevalence of antenatal HBsAg carriage was found, with a consistently significant decline among the three cohorts for the years 2007-2008 and 2010-2015, providing evidence that universal hepatitis B vaccination in infancy has reduced significantly antenatal prevalence of HBsAg carriage in Hong Kong.

Long-term Protection Against the Hepatitis B Virus Detected Through an Early Response to a Booster Dose Injection

Objective

To determine the duration of protection conferred by the hepatitis B (HB) vaccination and the necessity of a booster dose.

Methods

Immediately after the initial blood sampling, 252 youths (aged 18.8-20.5 years, 52% females) with a history of neonatal HB vaccination with one dose of the HB vaccine received a booster. Serum concentrations of antibodies against the HB surface antigen were assessed in samples collected before and 10-14 days after the booster. Seroconversion from concentrations <10 to ≥10 IU/L were defined as a positive immune response.

Results

Of the 252 participants, 131 were serosusceptible and 114 responded.

Conclusions

Nearly 90% of young people preserved their long-term protection; the results of this study do not support the use of an HB booster vaccination.

Long-term persistence of immunity after hepatitis B vaccination: Is this substantiated by the literature?

Hepatitis B vaccination is held to provide life-long protection against hepatitis B virus (HBV) infection, but evidence for this notion remains wanting, since no studies have assessed the vaccinees in their fourth decade of life. Indeed, there are several reports indicating that despite vaccination in infancy, the prevalence of HBV infection still increased with age in the vaccinees, and that both anti-HBs titer and anamnestic response declined with age. Clearly it is time to clarify the long-term protection conferred by vaccination in infancy, and to implement remedial measures such as booster doses of vaccine in subjects without immunoprotection.

Immune persistence after hepatitis B vaccination in infancy - Fact or fancy?

The hepatitis B vaccine has been introduced for more than 3 decades. In Hong Kong, excellent vaccine coverage through an efficient public health care system, together with supplemental programmes and easy availability of the vaccine, meant that most young pregnant women, and university students at entrance, should have been protected. Yet significant correlations in the prevalence of HBV infection with age were found in these groups of subjects, increasing from low to high endemicity rates from late teenage to the early twenties. This can only be attributed to vaccine failure, and there is cumulating evidence that several factors are involved, including the failure to respond to a primary series of hepatitis B vaccination in infancy, the waning of antibody titer with age, and loss of anamnestic response in a significant portion of the vaccinees. The duration of protection conferred by hepatitis B vaccination in infancy should be re-examined and remedial measures undertaken if its long term protection is found to be insufficient. Otherwise, the efforts to control HBV infection, especially in high endemicity regions, with universal vaccination in infancy would be rendered futile.

Effects of Risk Factors on Anti-HBs Development in Hepatitis B Vaccinated and Nonvaccinated Populations

Hepatitis B infection is still a major global health problem even though safe and effective vaccines have been available for more than 30 years. Although development of protective antibody to hepatitis B surface antigen (anti-HBs) is a common phenomenon after vaccination as well as natural infection, sometimes it does not appear even after complete vaccination. In the present study, whether the impairment of the development of anti-HBs in naturally infected and/or vaccinated populations is associated with immunomodulating risk factors (i.e., age, gender, smoking, and diabetes) and/or other risk factors (i.e., socioeconomic status, dental, and saloon exposure) was investigated through a cross-sectional study. Among 204 nonvaccinated patients, 132 (64.7%) tested positive for anti-HBc, indicating that they had been exposed to hepatitis B virus (HBV) at least once in their lifetime. Exposure to HBV (anti-HBc positive) was significantly higher among low-income people, dental exposed, and saloon users. Among anti-HBc positive patients, only 44 (33.3%) developed natural immunity with anti-HBs. Impairment in anti-HBs formation was found to be significantly high among cigarette smokers. However, no significant association of anti-HBs development was observed with age, gender, socioeconomic status, diabetes, dental exposure, and using saloon. Consistently, the frequency of developing protective anti-HBs (≥10 IU/L) among a vaccinated population was almost nine times less among smokers. These data suggest that anti-HBs development, either naturally or after vaccination, is significantly lower among smokers. It emphasizes the need to check the anti-HBs status in smokers after vaccination, and a booster vaccination should be administered if the anti-HBs antibody titer decreases below the protective level.

Chimeric hepatitis B virus (HBV)/hepatitis C virus (HCV) subviral envelope particles induce efficient anti-HCV antibody production in animals pre-immunized with HBV vaccine

The development of an effective, affordable prophylactic vaccine against hepatitis C virus (HCV) remains a medical priority. The recently described chimeric HBV-HCV subviral envelope particles could potentially be used for this purpose, as they could be produced by industrial procedures adapted from those established for the hepatitis B virus (HBV) vaccine. We show here, in an animal model, that pre-existing immunity acquired through HBV vaccination does not influence the immunogenicity of the HCV E2 protein presented by these chimeric particles. Thus, these chimeric HBV-HCV subviral envelope particles could potentially be used as a booster in individuals previously vaccinated against HBV, to induce protective immunity to HCV.