القيسي, عبداللهمطاعن, علي2025-07-292025https://hdl.handle.net/20.500.14154/76007Particularly in endemic areas such as Jazan, Saudi Arabia, hepatitis B virus (HBV) remains a major public health issue. Vaccination is believed to be amongst the most effective ways to control HBV infection. However, the long-term immunity of the HBV and the effect of the booster dose has not been well-studied. This research aimed to determine the long-term immunity from childhood HBV vaccination among Jazan University undergraduate students and to evaluate how well a booster dose helped restore protective antibody levels. The study was based on a cross-sectional approach with 1,426 22 to 25-year-old students who had finished their childhood main vaccination series. Serologic analysis showed that 87.8 percent of subjects had non-protective anti-HBs antibody levels (<10 mL/ml) at the time of the study, which points to partial immunity erosion. Later, 168 low antibody titer patients got a booster dose of the HBV vaccine. Follow-up tests revealed 100 percent seroconversion among all students who were followed up, with a notable rise in post-booster titers (mean: 526.6 mIU/mL), indicating the importance to the booster dose to restore immunity. Though early childhood immunization is effective, the results underline the decrease of measurable humoral immunity in young adults, but they also point to a strong anamnestic reaction to the second vaccination. Some body's immunological memory is mostly intact, though their circulating antibodies may be depleted. previous studies suggest genetic factors could influence vaccine response, particularly variations in immune-related genes such as HLA, IL6, and TNFα. The study supports the use of targeted serological monitoring and selective booster shots in high-risk groups, including health students, and suggests governmental evaluation of including booster evaluations into national vaccination frameworks.Particularly in endemic areas such as Jazan, Saudi Arabia, hepatitis B virus (HBV) remains a major public health issue. Vaccination is believed to be amongst the most effective ways to control HBV infection. However, the long-term immunity of the HBV and the effect of the booster dose has not been well-studied. This research aimed to determine the long-term immunity from childhood HBV vaccination among Jazan University undergraduate students and to evaluate how well a booster dose helped restore protective antibody levels. The study was based on a cross-sectional approach with 1,426 22 to 25-year-old students who had finished their childhood main vaccination series. Serologic analysis showed that 87.8 percent of subjects had non-protective anti-HBs antibody levels (<10 mL/ml) at the time of the study, which points to partial immunity erosion. Later, 168 low antibody titer patients got a booster dose of the HBV vaccine. Follow-up tests revealed 100 percent seroconversion among all students who were followed up, with a notable rise in post-booster titers (mean: 526.6 mIU/mL), indicating the importance to the booster dose to restore immunity. Though early childhood immunization is effective, the results underline the decrease of measurable humoral immunity in young adults, but they also point to a strong anamnestic reaction to the second vaccination. Some body's immunological memory is mostly intact, though their circulating antibodies may be depleted. previous studies suggest genetic factors could influence vaccine response, particularly variations in immune-related genes such as HLA, IL6, and TNFα. The study supports the use of targeted serological monitoring and selective booster shots in high-risk groups, including health students, and suggests governmental evaluation of including booster evaluations into national vaccination frameworks.55en-USالمختبراتالتهاب الكبديطلاب جامعة جازانThesis