Will Infant Hepatitis B Vaccination Protect Into Adulthood?: Extended Canadian Experience After a 2-, 4- and 6-month Immunization Schedule

Impact of the Universal Implementation of Adolescent Hepatitis B Vaccination in Spain

The aim of this study was to analyse the impact of the introduction of universal adolescent HBV vaccination on the incidence of acute hepatitis B virus (HBV) infections. Acute HBV cases reported to the Spanish National Epidemiological Surveillance Network between 2005 and 2021 were included. For regions starting adolescent vaccination in 1991-1993 and in 1994-1996, HBV incidence rates were compared by calculating the incidence rate ratio (IRR) and 95% confidence interval (CI). We also analysed the 2017 Spanish national seroprevalence survey data. The overall acute HBV incidence per 100,000 persons was 1.54 in 2005 and 0.64 in 2021 (p < 0.001). The incidence in 2014-2021 was lower for regions that started adolescent vaccination in 1991-1993 rather than in 1994-1996 (IRR 0.76; 95% CI 0.72-0.83; p < 0.001). In the 20-29 age group, incidence in regions that started adolescent vaccination in 1991-1993 was also lower (IRR 0.87; 95% CI 0.77-0.98; p = 0.02 in 2005-2013 and IRR 0.71; 95% CI 0.56-0·90; p < 0.001 in 2014-2021). Anti-HBc prevalence in the 35-39 age group was lower in the regions that started vaccination earlier, although the difference was not statistically significant (p = 0.09). Acute HBV incidence decreased more in the young adult population in regions that began adolescent vaccination earlier. Maintaining high universal vaccination coverage in the first year of life and in at-risk groups is necessary to achieve HBV elimination by 2030.

Prevalence of vaccine-derived hepatitis B surface antibodies in children and adolescents in Germany: results from a population-based survey, 2014-2017

INTRODUCTION

Childhood vaccination against hepatitis B has been recommended in Germany since 1995. WHO defines a primary vaccination series as successful if the initial hepatitis B surface antibody (anti-HBs) level is ≥ 10 IU/L directly after vaccination. Anti-HBs levels vary depending on the number of doses, type of vaccine, and time interval between the last two doses. In 2021, Germany began to recommend three instead of four doses of polyvalent hepatitis-B-containing vaccines. Our aim was to estimate the proportion of vaccinated children in Germany with anti-HBs levels < 10 IU/L, 10-99 IU/L, and ≥ 100 IU/L by number and type of vaccine, and assess if number of doses and compliance with recommended time interval between the last two doses are associated with an anti-HBs level ≥ 10 IU/L when considering type of vaccine and time since last dose.

METHODS

We used data from a national cross-sectional study (2014-2017) of children (3-17 years). We excluded participants with unknown vaccination dates, unreadable or incomplete vaccination cards, and hepatitis B virus (HBV)-positive participants. We defined a recommended schedule as a vaccination series with at least six months between the two last doses and having three doses or more. We calculated weighted anti-HBs sero-prevalence for three anti-HBs levels: < 10 IU/L, 10-99 IU/L and ≥ 100 IU/L. We fitted two logistic regression models to examine the relationship between number of doses and recommended schedule on anti-HBs levels (≥ 10 IU/L and ≥ 100 IU/L) considering time since last dose and type of vaccine (Infanrix, Hexavac, Monovalent).

RESULTS

We included 2,489 participants. The weighted proportion of vaccinated children per anti-HBs level was < 10 IU/L: 36.3% [95%CI 34.0-38.7%], 10-99 IU/L: 35.7% [33.2-38.2%] and ≥ 100 IU/L: 28.0% [25.9-30.2%]. We did not find an association between a recommended schedule of three versus four doses and anti-HBs ≥ 10 IU/L or ≥ 100 IU/L.

CONCLUSIONS

Anti-HBs levels in later childhood were about equal, whether children received three or four doses. This implies that the change in the recommendations does not affect the anti-HBs level among children in Germany. Future studies are needed on the association of anti-HBs levels and adequate sustained protection against HBV.

Levels of hepatitis B antibody titers are affected by age and doses gap time in children from a high endemic area of the western Amazon

BACKGROUND

Despite completion of the vaccine schedule for hepatitis B virus (HBV), children may display levels of HBV surface antibodies (anti-HBs) that are considered inadequate for sufficient protection (<10 IU/L).

AIMS

Our aim was to investigate if age and gap time between HBV vaccine doses may negatively affect the levels of anti-HBs in children, and if these relationships are modified by sex.

METHODS

In a high-endemic HBV region of the western Brazilian Amazon we enrolled children who had completed the HBV vaccine schedule. All children underwent analysis of anti-HBs and a clinical examination.

RESULTS

We included 522 children (mean age 4.3 ± 0.8 years; 50% male). Median anti-HBs was 28.4 [interquartile range (IQR) 5.4 to 128.6] IU/L and 32% had anti-HBs <10 IU/L. The median gap time from last to preceding dose was 2.4 [IQR 2.1 to 3.3] months. Levels of anti-HBs decreased with higher age (-42% per year increase [95%CI -56% to -24%], p<0.001), but not with longer gap time (+23% per month increase [95%CI -16% to +62%], p = 0.249). After adjusting for relevant confounders, gap time became significant (p = 0.032) and age remained a significant predictor of anti-HBs (p<0.001).

CONCLUSION

One third of assessed children displayed anti-HBs <10 IU/L. Levels of anti-HBs decreased with higher age and increased with longer gap time between the last two doses.

Will Infant Hepatitis B Immunization Protect Adults?

Globally, infant hepatitis B virus (HBV) immunization programs are markedly reducing the rate of chronic HBV infections among children <5 years of age. Desirable improvements include increased birth dose coverage and better prevention of perinatal HBV transmission. Follow-up studies show that by the teenage years most of those immunized as infants have lost circulating anti-HBs antibody and some fail to respond to challenge HBV vaccination, implying loss of protection from infection. With high exposure to HBV, such individuals can develop breakthrough HBV infection but this rarely leads to chronic infection, the main goal of prevention programs. While longer-term follow-up studies into adulthood are needed, current evidence does not support a need for booster immunization of otherwise healthy teens or young adults.

From infancy and beyond… ensuring a lifetime of hepatitis B virus (HBV) vaccine-induced immunity

Despite the long-term efficacy and immune persistence observed following HBV vaccination of infants, the need for a booster dose following infant immunization continues to be deliberated. Evidence from HBV booster dose response studies and long-term immunization program reviews are the basis for the recommendation that a vaccine booster is not necessary. However, further studies continue to emerge and highlight the need for standardization among observational studies in order to appropriately compare outcomes. There is an assumption that neonatal and infant (within 12 months of age) vaccine immune responses are equivalent; however, evidence exists for distinct vaccine responses within the first year of life. HBV vaccine programs have evolved over time, particularly regarding the type and dosage of vaccine used. Several universal neonatal immunization programs initially incorporated a 2.5 μg dosage (Recombivax-HB, Merck). This dosage has been shown in multiple long-term studies and meta-analyses to be associated with a lower primary response, decreased antibody persistence over time, and a reduced booster response 10 to 20 years following immunization. Ongoing surveillance of this and other HBV neonatally-vaccinated populations, particularly in low endemic regions, is necessary to understand the impact on long-term protection in order to ensure lifelong protection against hepatitis B infection.

Persistence of hepatitis B immune memory until 9-10 years of age following hepatitis B vaccination at birth and DTaP-IPV-HB-PRP∼T vaccination at 2, 4 and 6 months

OBJECTIVE

To evaluate the long-term persistence of anti-hepatitis B surface (HBs) antibodies and the response to a HB challenge re-vaccination in children who had received a primary series of DTaP-IPV-HB-PRP∼T (Hexaxim™) or DTaP-IPV-HB/PRP∼T (Infanrix hexa™).

METHODS

Two cohorts of participants who had previously received HB vaccine at birth followed by either DTaP-IPV-HB-PRP∼T or DTaP-IPV-HB/PRP∼T co-administered with PCV7 at 2, 4, 6 months of age in a randomized, Phase III, observer-blind study in Thailand, were followed up for anti-HBs antibodies (geometric mean concentrations [GMCs] and seroprotection [SP] rate [% of participants with a titer ≥10 mIU/mL]) at 12-18 months of age and 9-10 years of age. A monovalent HB challenge re-vaccination was administered at 9-10 years of age and the anamnestic response was evaluated.

RESULTS

Anti-HBs GMCs and SP rates in the DTaP-IPV-HB-PRP∼T and DTaP-IPV-HB/PRP∼T groups were high and similar post-primary vaccination series (2477 mIU/mL and 99.5% and 2442 mIU/mL and 99.5%, respectively) and declined to a similar extent in each group at 12-18 months (154.5 mIU/mL and 90.8% and 162.3 mIU/mL and 96.5%, respectively). Antibody levels further declined at 9-10 years of age (13.3 mIU/mL and 49.3% and 8.0 mIU/mL and 42.9%) and a strong anamnestic response occurred in each group post-HB challenge re-vaccination (92.8% and 98.7%, respectively).

CONCLUSION

The kinetics of long-term anti-HBs antibody persistence were similar following a primary series of DTaP-IPV-HB-PRP∼T or DTaP-IPV-HB/PRP∼T. The response to a subsequent HB challenge re-vaccination was strong and similar in each group, demonstrating persisting immune memory.

Revaccination against hepatitis B in late teenagers who received vaccination during infancy: Yes or no?

The significance of vaccination against hepatitis B during infancy is recognized worldwide, however, whether booster or revaccination after a period of time following the primary vaccination is required remains controversial. Recently, cross-sectional epidemiological surveys found that HBsAg prevalence in subjects born after the implementation of mass vaccination was increased with age, which was attributed to waning of anti-HBs over time. However, comprehensive analysis of the closely related cross-sectional surveys showed that the age-specific increased HBsAg prevalence was more likely associated with the carry-over of the infection occurred in early life, likely due to imperfect coverage of hepatitis B vaccination at the beginning of its introduction. Latest studies showed that booster response could be observed in the majority of individuals vaccinated 30 years ago. Moreover, confirmed breakthrough HBV infection with severe consequences in successfully vaccinated individuals is extremely rare. Thus far no compelling evidence has been acquired to support booster vaccination in adolescence. The uncertainty regarding the duration of protection of hepatitis B vaccination, especially beyond 30 years after the primary vaccination, merits a systematically designed study to follow the same cohort of participants longitudinally, which differs from the cross-sectional studies reported previously, can hopefully offer more direct evidence to help us to determine whether revaccination of hepatitis B vaccine is necessary.