Monitoring the efficacy of infant hepatitis B vaccination and revaccination in 0- to 8-year-old children: Protective anti-HBs levels and cellular immune responses

Reduced protective efficacy of hepatitis B vaccine among fully vaccinated children in Ethiopia

BACKGROUND

Hepatitis B vaccination is recommended for all children at birth within 24 hours or during childhood.

OBJECTIVE

This study was aimed to evaluate protective efficacy of hepatitis B vaccine and estimate the sero-prevalence of hepatitis B virus infection among vaccinated children.

MATERIALS AND METHODS

A community-based cross-sectional study was conducted from March, 2021 to October, 2021 in Debre Markos town. A simple random sampling technique was used to select 165 fully vaccinated children aged 5-12 years old. A serum sample was used to determine hepatitis B surface antigen (HBsAg), anti-hepatitis B core antibody (anti-HBc), anti-hepatitis B surface antibody titer (anti-HBs) using ELISA.

RESULTS

The seroprevalence of HBsAg and anti-HBc anti-body was found to be 4.2% and 4.8% respectively. Of 165 fully vaccinated children, 129 (78.2%) had anti-HBs titer ≥ 10 mIU/ml. Among 129 sero-protected children, 76 (58.9%) were hypo-responders whereas the rest 53 (41.1%) were good responders. Those children within the age group of 5-7 years were 2.9 times (AOR: 2.873, 95% CI: 1.156, 7.141) (P<0.023) more likely to respond to HBV vaccine. Multivariate logistic regression revealed that children who were born from HBV positive mothers (AOR 3.917, 95% CI: 1.456, 5.365, P<0.027) and those who had history of injectable medications (AOR 9.232, 95% CI: 1.503, 11.697, P<0.016) were more likely to be HBsAg positive. Children who had history of hospital admission (AOR 6.973, 95% CI: 1.495, 8.530, P<0.013) were more likely to be anti-HBcAb positive.

CONCLUSIONS

There was an intermediate prevalence of childhood HBV infection despite being vaccinated suggesting low protective efficacy of hepatitis B vaccine in the study area.

Monocytic MDSCs homing to thymus contribute to age-related CD8+ T cell tolerance of HBV

Hepatitis B virus exposure in children usually develops into chronic hepatitis B (CHB). Although hepatitis B surface antigen (HBsAg)–specific CD8⁺ T cells contribute to resolve HBV infection, they are preferentially undetected in CHB patients. Moreover, the mechanism for this rarely detected HBsAg-specific CD8⁺ T cells remains unexplored. We herein found that the frequency of HBsAg-specific CD8⁺ T cells was inversely correlated with expansion of monocytic myeloid-derived suppressor cells (mMDSCs) in young rather than in adult CHB patients, and CCR9 was upregulated by HBsAg on mMDSCs via activation of ERK1/2 and IL-6. Sequentially, the interaction between CCL25 and CCR9 mediated thymic homing of mMDSCs, which caused the cross-presentation, transferring of peripheral HBsAg into the thymic medulla, and then promoted death of HBsAg-specific CD8⁺ thymocytes. In mice, adoptive transfer of mMDSCs selectively obliterated HBsAg-specific CD8⁺ T cells and facilitated persistence of HBV in a CCR9-dependent manner. Taken together, our results uncovered a novel mechanism for establishing specific CD8⁺ tolerance to HBsAg in chronic HBV infection.

Hepatitis B Vaccination in Children With Ongoing Cancer Treatment: A Safety and Efficacy Study of Super-Accelerated Vaccination Scheme

OBJECTIVE

Children with cancer have an increased risk for hepatitis B virus (HBV) infections due to chemotherapy-induced secondary immunodeficiency and frequent blood transfusions. The aim of this study is to evaluate the efficacy and safety of hepatitis B vaccination during the intensive induction chemotherapy in children with cancer found to be seronegative for hepatitis B on admission.

MATERIALS AND METHODS

Children newly diagnosed with cancer were evaluated for the presence of hepatitis B surface antigen (HBsAg) and antibody on admission. The children negative for both were included in the study. A super-accelerated vaccination scheme (3 booster doses at days 1-5, 8-12, and 28-33) was administered to these seronegative children concurrently with induction chemotherapy. Antibody response was checked 4-8 weeks after the last vaccination and 6 months after the end of the treatment.

RESULTS

Eleven out of 122 children were seronegative for hepatitis B on admission (9%). Acute lymphoblastic leukemia, lymphoma, and solid tumors were diagnosed in 5, 4, and 2 children, respectively. Complete seroconversion was achieved in 4-8 weeks after the last vaccination with high titers of anti-HBs antibody, and all patients remained antibody-positive until 6 months after the completion of chemotherapy.

CONCLUSION

The risk of transfusion-related infections increases with a number of transfused products and donor exposures, and it is more significant for immunosuppressed children with hematologic and oncologic malignancies. Hepatitis B vaccination could safely be applied with brisk and sustained responses in this vulnerable population, based on the local epidemiological data.

Anti-HBs levels in children under the age of two years born to HBV carrier mothers after immunoprophylaxis: a multicenter cross-sectional study

Background

Serological testing for the presence of Hepatitis B Virus (HBV) markers and anti-HBs titers in infants born to HBsAg positive women is critically important for estimation in immunisation programme.

Methods

This was a multi-center and cross-sectional study conducted in Zhejiang province, China. Children aged 7 to 24 months born to HBsAg positive women during December 2018 to February 2019, completed additional HBV serological markers screening. We indicated distribution of HBV serological markers and anti-HBs titers in children. Multiple logistic regression model with adjusted odds ratio and 95% confidence interval (OR_adj and 95% CI) was used to explore the factors associated with inadequate immune response (anti-HBs titers< 100 mIU/ml) among children.

Results

A total of 1849 children were included. Overall 25 children tested HBsAg positive, giving HBsAg positive rate of 1.35%(95%CI: 0.83-1.88%). 92.00% (23/25) HBsAg positive children were delivered by HBeAg positive mothers. The proportion of protective seroconversion (anti-HBs titers≥10mIU/ml) was 99.29% in all children, and 86.48% children were reported with adequate anti-HBs titers (≥100mIU/ml).We found a significant higher proportions of early antenatal health care (< 13 gestational weeks), and term birth in children with adequate response compared with inadequate response (all P < 0.05). Logistic regression showed preterm birth was a negative factor for inadequate anti-HBs titers (OR_adj = 1.868,95%CI 1.132-3.085,P = 0.015).

Conclusions

Children delivered by HBeAg positive mothers had higher risk of vertical transmission of HBV, despite completion of 3 doses of hepatitis B vaccine and HBIG injection. Inadequate anti-HBs level was significantly associated with preterm birth in HBsAg positive women.

Elimination of hepatitis B virus infection in children: experience and challenge in China

ABSTRACT

Chronic hepatitis B virus (HBV) infection is a serious health issue because of its severe sequelae. Prevention of mother-to-child transmission (MTCT) of HBV is critical to eliminate chronic HBV infection. Here, we reviewed the progress toward the elimination of HBV infection in children in China in the recent decade. A universal hepatitis B vaccination program started from 2002 has been intensified, with the coverage of timely birth dose >95% of all newborn infants from 2012. Since 2011, China has taken a nationwide program to administer hepatitis B immunoglobulin (HBIG) with free of charge in all neonates of HBV-infected mothers, leading to a significant increment of timely use of HBIG. The prevalence of hepatitis B surface antigen (HBsAg) was declined from around 10% among children in 1980s to <0.5% among children born after 2011. Administration of oral antiviral agents in HBV-infected pregnant women with HBV DNA >2 × 105 U/mL during the third trimester is increasing, which will further reduce MTCT of HBV. However, there are some challenges in the elimination of HBV infection in children, which need to overcome by the concerted efforts. Nevertheless, it is anticipated that China will achieve the goal set by the World Health Organization that the prevalence of HBsAg in children aged <5 years is ≤0.1% by 2030.

HLA-DPB1 alleles in hepatitis B vaccine response: A meta-analysis

BACKGROUND

The role of the HLA-DRB1 and HLA-DQB1 genes in the antibody response to hepatitis B (HB) vaccine has been well established; however, the involvement of the HLA-DPB1 allele in the HB vaccine immune response remained to be clarified by a systematic review.

METHODS

A meta-analysis was performed in which databases were searched for relevant studies published in English or Chinese up until June 1, 2020. Six studies were identified and a total of 10 alleles were processed into statistical processing in this meta-analysis.

RESULTS

Three thousand one hundred forty four subjects (including 2477 responders and 667 non-responders) were included in this research. Alleles HLA-DPB1∗02:02, DPB1∗03:01, DPB1∗04:01, DPB1∗04:02, and DPB1∗14:01 were found to be associated with a significant increase in the antibody response to HB vaccine, and their pooled odds ratios (ORs) were 4.53, 1.57, 3.33, 4.20, and 1.79, respectively; whereas DPB1∗05:01 (OR = 0.73) showed the opposite correlation.

CONCLUSIONS

These findings suggested that specific HLA-DPB1 alleles are associated with the antibody response to HB vaccine.

[Hepatitis B vaccine and liver cancer]

Hepatitis B Virus (HBV) chronic infection contributes to a high risk of hepatocellular cancer (HCC) development. HBV is a strong cancer inducer, due to natural history of infection, virological characteristics and viral DNA integrations events in host genome. Prolonged infection and high viral loads, particularly frequent in patients infected in childhood, are risk factors of HCC development for patients with HBV chronic infection. A HBV vaccine, based on immunization against the surface protein HBs, showed a strong efficacy to prevent chronic HBV infection. The development of universal neonatal vaccination programmes contributed to the decrease of HBV chronic infection incidence in children of high endemic areas. Although HBs antibodies levels diminished years after vaccination, HBV neonatal vaccination programmes led to a lower incidence of chronic HBV infection among young adults. The decrease of HBV chronic infection incidence was associated to a reduction of HCC incidence in children and young adults from areas with a high prevalence of HBV infection.

Circulating follicular helper T cells and subsets are associated with immune response to hepatitis B vaccination

Around 5-10% of healthy vaccinees lack or produce an inadequate antibody response following receipt of a standard hepatitis B vaccination regimen. Studying immune response to hepatitis B vaccination could promote researches of immunological events contributing to this poor response. To address this, we investigated follicular helper T (Tfh) cells and firstly demonstrated similar kinetics between circulating Tfh (cTfh) cells and Tfh cells derived from mice spleen after hepatitis B vaccination. And cTfh cells were positively associated with anti-HBs at one week after vaccination (D7). Furthermore, we found PBMCs stimulated by HBsAg showed preferential activation of CXCR3^- Tfh cells subsets in vitro. The expression of transcription factor BCL6 in CD4⁺ T cell significantly differed between D7 and four weeks after vaccination (D28). However, dynamic curve of CD19⁺ B cells tended to rise then fall but no significant trends were observed. Our findings revealed a decrease in cTfh cells and subset skewing contribute to reduced antibody responses in immune response to hepatitis B vaccination, which indicated the importance of Tfh cell in facilitating the optimization of vaccine efficacy.

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.