How often should I check my antibody titer if I am in regular contact with hepatitis B carriers? How many years to how often is appropriate? The natural population (non-Hepatitis B) can be roughly subdivided into the following three categories: 1. People who have no resistance to Hepatitis B: these people account for about 20%, and the proportion of people under 20 years old is slightly reduced, because of the popularization of the vaccine, this group of people should in principle undergo the whole vaccination (016 method), and the antibody output rate of this group of people is about 85-95%, and 40% of the people can guarantee for 10 years, 30% of the people can ensure for 5 years, and 20% of the people can guarantee for 3 years, therefore, the antibody test should be carried out one month after vaccination. Therefore, the antibody test should be conducted one month after the vaccination is completed, and the antibody value will predict the approximate persistence time of the vaccinated person. 2, weak resistance to hepatitis B: this kind of people are essentially on the verge of vaccine booster, the surface antibody is close to 100U or even has been lower than 100U, this kind of people account for about 15% of the non-Hepatitis B population, and the older people can account for 35%. 3, strong resistance to hepatitis B: this group of people do not need booster vaccination within 3-5 years, this group of people accounted for about 60% of the non-B population, 25-40 years old people can account for 70%. In addition, about 5-10% of the vaccinated population have poor vaccine production and need to be vaccinated in additional doses and times.