[Variations of hepatitis B virus infection epidemic pattern after long-term HBV vaccine immunization]

To study the epidemic pattern and trend of HBV infection in the area where the people had been immunized by HBV vaccine for 20 years.

The whole sampling method was applied in combination with cross-sectional investigation. Blood samples were taken from every member of families. Markers of HBV infection were determined by using solid-phase radioimmunoassay (SPRIA).

(1) The average HBsAg positive rate was 7.5%. The positive rate of markers for HBV infection of 0-19 years old subjects were lower than those of > or = 20 years old subjects. (2) The positive rate of HBsAg of 0-19 years old subjects in 1985 was higher than that in 2005. The anti-HBs positive rate in 1985 stemmed to be higher with age. It was 12.4% in 1- age group to 53.8% in >60 years age group. While the result of 2005 showed that the anti-HBs positive rate of 0-19 years old subjects dropped with age. The anti-HBc positive rate in 1985 also tended to be higher with age. But the result of 2005 showed that the rate of 0-19 years old subjects was just 1.4% to 16.8%.

The epidemic patterns of HBV infection have had significant variations in the target population. HBV vaccine immunization has obtained excellent efficacy.