Journal of Vaccine Research 2024, Vol.14, No.3, 107-119 http://medscipublisher.com/index.php/jvr 111 Table 1 Prevalence of HBsAg and anti-HBs in children and young adults after universal vaccination in selected regions (Adopted from Zhao et al., 2020) Region Initiation of Universal vaccination Study period Age (Y) No HBsAg+(%) Anti-HBs+(%) Alaska, USA April 1983 12/1993–1/1994 2–5 121 0 (0) 30/120 (25.0) 6–10 150 0 (0) 56/146 (38.4) 11–15 118 9 (7.6) 68/87 (78.2) 16–20 60 11 (18.3) 28/30 (93.3) 21–25 62 13 (21.0) 17/21 (81.0) 26–30 92 20 (21.7) 19/20 (95.0) Taiwan 1986 1/1/2014–12/31/2014 <1–29 3299 17 (0.52) 1564 (47.4) Singapore 1987 8/2008–7/2010 1–6 400 0 (0) 255 (63.8) 7–12 400 1 (0.30) 131 (32.8) 13–17 400 3 (0.75) 94 (23.5) China 2002 9/2006–10/2006 1–<5 13276 -1 -71.2 5–<10 11909 -1.4 -55.5 10–<15 11844 -3.2 -57.5 10/2014–12/2014 >0.6–3 1270 2 (0.16) 1210 (95.3) 4–6 822 3 (0.36) 733 (89.2) 7–9 752 1 (0.13) 662 (88.0) 10–12 598 6 (1.00) 504 (84.3) 1–4 12681 -0.3 -71.6 5–14 9738 -0.9 -52.9 15–29 9294 -4.4 -56.9 Table caption: Table 1 shows the prevalence of Hepatitis B surface antigen (HBsAg) and anti-Hepatitis B surface antibody (anti-HBs) in children and young adults after the implementation of universal vaccination in different regions. The data indicate that universal vaccination has significantly reduced the HBsAg positivity rates in Alaska, Taiwan, Singapore, and China, especially among children. However, HBsAg positivity rates tend to increase with age, particularly in Alaska. On the other hand, the anti-HBs positivity rates improve with age, reflecting good long-term immunity. Data from Taiwan and China show that after universal vaccination, the HBsAg positivity rates remain low, especially in children, with almost zero positivity. These results demonstrate the significant effectiveness of universal vaccination in controlling the spread of the Hepatitis B virus (Adopted from Zhao et al., 2020) 4.2 Global immunization programs Global immunization programs have made significant strides in reducing the prevalence of HBV infection. According to the World Health Organization (WHO), universal hepatitis B vaccination has been implemented in 189 countries, leading to a dramatic decrease in the prevalence of HBsAg among children under five years of age, from 4.7% in the pre-vaccine era to 1.3% in 2015 (Hutin et al., 2018; Zhao et al., 2020). This success is attributed to the widespread adoption of the hepatitis B vaccine in national immunization schedules, often starting with a birth dose followed by additional doses during infancy (Hutin et al., 2018). The Global Alliance for Vaccines and Immunization (GAVI) has played a crucial role in supporting the introduction of hepatitis B vaccines in low-income countries. This has resulted in measurable reductions in HBV-related morbidity and mortality. For instance, in Taiwan, the prevalence of chronic HBV infection in children has declined by more than 90% following the implementation of universal vaccination (Shepard et al., 2006). However, challenges remain in achieving optimal vaccination coverage. In many countries, particularly in sub-Saharan Africa, the timely administration of the birth dose is not routinely practiced, which hampers efforts to prevent MTCT of HBV (Tall et al., 2021). Studies have shown that the addition of a birth dose to the existing vaccination schedule can further reduce HBV transmission, highlighting the need for its integration into routine immunization programs (Tall et al., 2021). Efforts to overcome social and economic barriers to vaccination are essential for the global control of HBV. The WHO's Global Hepatitis Program provides a framework for countries to develop and implement effective national
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