Elimination of Hepatitis B Virus Infection in Children: China’s Experience

0
0
0

Elimination of Hepatitis B Virus Infection in Children: Experience and Challenge in China

Chronic hepatitis B virus (HBV) infection remains a significant global health burden due to its association with liver cirrhosis, hepatocellular carcinoma, and other malignancies. In China, where HBV prevalence once exceeded 10% in the general population, concerted efforts over decades have drastically reduced transmission, particularly among children. This article examines China’s strategies, achievements, and remaining challenges in eliminating pediatric HBV infection, focusing on immunization programs, prevention of mother-to-child transmission (MTCT), antiviral interventions, and epidemiological trends.

Evolution of Hepatitis B Vaccination Programs

China introduced hepatitis B vaccination in 1982, initially relying on plasma-derived vaccines. By 1998, recombinant yeast and Chinese Hamster Ovary (CHO) vaccines replaced plasma-based products, improving safety and scalability. A pivotal shift occurred in 2002 with the launch of a universal vaccination program providing free three-dose regimens (0-, 1-, and 6-month schedule) to all newborns. This initiative increased timely birth-dose coverage (within 24 hours) from 29.1% in 1997 to over 95% by 2012. Catch-up campaigns between 2009 and 2011 vaccinated 68 million children born from 1994 to 2001, further reducing susceptibility.

Preventing Mother-to-Child Transmission

MTCT is a primary route of HBV persistence. Before 2011, passive-active immunoprophylaxis—combining hepatitis B immunoglobulin (HBIG) and vaccination—was inconsistently applied due to cost barriers and logistical gaps. For example, HBIG coverage in Jiangsu Province was only 37.6% in 2002–2004. In July 2011, China implemented nationwide free HBIG for infants of HBsAg-positive mothers, boosting timely HBIG administration to 98% by 2016. Concurrently, prenatal screening for HBsAg improved, enabling targeted interventions.

High maternal viral load (HBV DNA >200,000 IU/mL) and HBeAg positivity are key risk factors for immunoprophylaxis failure. Studies show that 70–90% of infants exposed to HBeAg-positive mothers develop chronic infection without intervention. To address this, China introduced antiviral therapy for pregnant women with HBV DNA >200,000 IU/mL during the third trimester. Tenofovir and telbivudine are widely used, reducing MTCT rates to <2% in clinical trials. Updated 2020 guidelines recommend antiviral prophylaxis for this high-risk group, further curtailing vertical transmission.

Declining HBsAg Prevalence in Children

Universal vaccination and MTCT prevention have driven dramatic declines in pediatric HBV prevalence. National surveys reveal HBsAg rates dropped from 10% in the 1980s to 0.3% among children aged 1–4 years in 2014. Regional studies corroborate this trend:

  • Jiangsu Province (2014): 0.16% in children aged 0.6–3 years.
  • Chongqing (2012–2016): 0.48% in children aged 1–16 years.
  • Yunnan Province (2017): 0.71% in children aged 1.5–5.5 years.

Notably, children born after 2011—following HBIG universalization—exhibit HBsAg prevalence below 0.5%, positioning China to meet the WHO target of ≤0.1% in children under five by 2030.

Improved Efficacy of Immunoprophylaxis

Post-2011 data demonstrate the success of combined HBIG and vaccination. In Jiangsu Province, MTCT rates fell from 10.3% to 5.8% among infants of HBeAg-positive mothers. A 2017–2018 multi-province study (Guangdong, Zhejiang, Shaanxi, Hebei) reported only 0.9% transmission among 4,112 infants. These outcomes align with global benchmarks, such as Hong Kong’s 4.4% MTCT rate under similar protocols.

Persistent Challenges

Despite progress, hurdles remain:

  1. Suboptimal Birth-Dose Coverage in Rural Areas
    While urban regions achieve >95% timely vaccination, rural and western areas lag. In 2015, Yunnan’s rural timely birth-dose coverage was 71.2%, contributing to higher HBsAg prevalence (1.57% in children aged 5.6–10.5 years). Mobile populations and healthcare access disparities exacerbate this gap.

  2. Delayed or Missed HBIG Administration
    Preterm birth, inadequate HBIG storage, and missed prenatal screening result in delayed HBIG use. In Ningbo (2013–2018), 19.4% of infants received HBIG beyond 24 hours. False-negative maternal HBsAg tests due to assay variability also hinder prophylaxis.

  3. Inadequate Post-Vaccination Serologic Testing (PVST)
    PVST rates remain low, with <50% compliance in targeted regions like Chongqing and Fujian. Parental reluctance and logistical barriers limit data accuracy on immunoprophylaxis efficacy.

  4. Antiviral Therapy Gaps
    Rural healthcare facilities often lack HBV DNA quantification capabilities, relying on HBeAg as a surrogate marker. However, 10% of HBeAg-negative mothers still have high viral loads (>200,000 IU/mL), risking MTCT. Enhancing diagnostic infrastructure and provider education is critical.

  5. Assay Accuracy Concerns
    Discrepancies in HBsAg testing—11.9% false positives in prenatal screens—undermine surveillance. Standardizing assays and confirmatory testing (e.g., neutralizing assays) is essential for reliable data.

Conclusion

China’s multipronged strategy—universal vaccination, HBIG universalization, and antiviral prophylaxis—has transformed HBV control, reducing childhood HBsAg prevalence twentyfold since the 1980s. Persistent challenges in rural healthcare access, diagnostic accuracy, and prophylaxis adherence require targeted investments. With continued refinement of MTCT prevention and equitable service delivery, China is poised to eliminate pediatric HBV infection, setting a global precedent for hepatitis eradication.

doi.org/10.1097/CM9.0000000000001791

Was this helpful?

0 / 0