METHODS: A thorough database search covered various sources using relevant keywords like "Hepatitis B virus genotypes", "HBV genotypes in Bangladesh", and "HBV clinical implications". The review synthesized findings and analyzed HBV genotype prevalence and clinical implications in Bangladesh.

RESULTS: Genotypes C and D collectively represent 82% of chronic hepatitis-B infection (CHB) cases in Bangladesh, underscoring their regional prevalence. The geographic context is pivotal in understanding HBV infection dynamics and disease progression in this area. Notably, genotype C and the presence of A1762T/G1764A mutations appear to have a distinct impact on disease development, potentially affecting the immune response in CHB patients. This highlights the need for tailored management approaches in this specific region. Further research is vital to confirm and elaborate on these findings, particularly in relation to how these mutations influence the host's immune response.

CONCLUSION AND CLINICAL SIGNIFICANCE: In summary, studies on HBV genotypes in Bangladesh stress the need for genotype-specific clinical considerations and more research to improve diagnostics and therapies.

Materials and methods: We developed a mathematical model based on the susceptible-infectious-recovered model to simulate the HBV-induced infection in children under the age of five at three different vaccination rates: 80, 90, and 95%. Additionally the impact of current vaccination coverage was assessed on HBV-induced death rates in the future. Moreover, we took advantage of the mathematical model to investigate the impact of negative bias toward girls in vaccination program on HBV-induced infection and death rates.

Results: The model simulations revealed that 10% increase in the vaccination rate from 80 to 90% can potentially contribute to the significant lowering (around 40%) of HBV-induced infection rate among children. When increased by 5% of vaccination rate from 90 to 95%, the HBV-infection rate is likely to be decreased by another 22%. Likewise, 44% reduction in HBV-induced death rate in the future (2050 onward) can potentially be achieved by 10% increase in the current vaccination rate from 80 to 90%, whereas 5% increase in the current vaccination rate (90-95%) may lead to 24% further reduction of death rate. These results underscored the significant impact of vaccination in reducing HBV-induced infection among children and future death rates in adults. Moreover, at 90% vaccination coverage, the negative bias of vaccination toward girls contributes to an increase of 15 and 12% of HBV-induced infection and death rates, respectively, in female subjects compared to their male counterparts.

Conclusion: The current vaccination coverage (80-90%) is further aggravated by untimely vaccination, dropouts from vaccination program, and negative bias toward girls in vaccination program. Therefore, if the current situation persists, it will not be possible to accomplish the required reduction in HBV-induced infection and death rates by 2030, according to the SDG guidelines. Moreover negative bias in the vaccination program may intensify the HBV-induced infection and death rates in the future.

Clinical significance: In light of the mathematical model, we suggest that the vaccination coverage should be increased to 95% without any negative bias toward girls. To accomplish this, the concerning authorities must ensure timely and full completion of the HBV vaccine schedules, reducing dropouts from vaccination program, and lastly preventing negative bias toward girls to uplift vaccination coverage to more than 95% with gender equality. Without these strategies, the necessary reduction in the HBV-induced infection and death rates in Bangladesh may not be attained per SDG directives.