Dynamic study on the anti-HBs level of immunized children born to HBsAg-positive and HBsAg-negative mothers in hyperendemic area of hepatitis B / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate the dynamic changes of the anti-HBs level among immunized newborn infants born to HBsAg-positive and HBsAg-negative mothers in hyper-endemic area of Hepatitis B.</p><p><b>METHODS</b>Infants who were regularly vaccinated with Hepatitis B vaccine and tested to be anti-HBs positive were divided into two groups according to HBsAg-positive or negative mothers in Long-an, Guangxi. Each subject was followed up 3 times during age 5 to 8. SPRIA was used to test HBsAg, anti-HBs and anti-HBc. Results During the follow-up period, positive rates of anti-HBs in children born to HBsAg-positive mothers ranged between 52.00% and 78.00%, and those with HBsAg-negative mothers was between 43.84% and 54.74%. GMT in two groups was between 55.36 mIU/ml and 95.66 mIU/ml as well as between 39.90 mIU/ml and 65.47 mIU/ml, respectively. There was no statistical significance in both positive rates and GMT between age groups. The anti-HBs level in the follow-up period of children born to HBsAg-positive mothers was higher than that of those born to HBsAg-negative mothers in the same age group. In the age group of 6-8 years with HBsAg-negative mothers, the positive rates in the follow-up period of children with high anti-HBs titers in the primary vaccination were 2.29-2.84 times of those with low titers. The anti-HBs titer of children in a follow-up period was lower than that in the primary vaccination, no matter whether they were born to HBsAg-positive mothers. However, the decline rate of children born to HBsAg-negative mothers was significantly higher than those born to HBsAg-positive mothers (84.91% vs. 61.54%; chi2 = 28.7982, P = 0.000). The incidence rate (25.64%) of a 4-fold increase in antibody titers of children born to HBsAg-positive mothers was significantly higher than that of children born to HBsAg-negative mothers (7.37%) from the primary vaccination to the follow-up period (chi2 = 6.7661, P = 0.009) with was 3.5 times of the latter. Subjects with HBsAg seroconvertion were those with low anti-HBs titers in primary vaccination.</p><p><b>CONCLUSION</b>The anti-HBs level decreased slowly in successfully immunized children from age 5 to 8. The chance of natural booster yielded by natural infection increased in immunized children born to HBsAg-positive mothers. The anti-HBs level in the primary vaccination played an important role in prevention of seroconversion of HBsAg.</p>

Long-term efficacy of infant hepatitis B immunization program / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To evaluate the long-term efficacy of infant hepatitis B (HB) immunization program on preventing hepatitis B virus (HBV) infection, and to assess its impact on the incidence of HB in children.</p><p><b>METHODS</b>Since 1986, the universal HB vaccination for newborn babies with standard, pediatric dose had been launched without serologic prescreening of pregnant women for HBsAg, in a high endemic county of Long-An. A hepatitis surveillance system was set up to evaluate the possible impact on the incidence of hepatitis B. To serologically evaluate the effectiveness of the program, a stratified random sampling of 1000 children in 1987 birth cohorts, who received plasma-derived HB vaccine, was recruited for long-term follow up at the age of 1 to 13 years. A cross-sectional seroepidemiological survey was conducted in the county in 1985, before the program, and in 2001, for 1551 children born in 1996-2000 who were administered yeast recombinant HB vaccine.</p><p><b>RESULTS</b>During the 1 to 13 years after the program, the rates of HBsAg-positive were 0.7% to 2.9% with an average of 1.7% and the protective rates were 83.5% to 96.6%. HBV infection rates were 1.1% tp 5.1% with an average of 2.4% and the protective rates were 93.5% to 98.4%. For the population aged 1 to 4 years who were immunized with recombinant HB vaccine, HBsAg positive rates were 1.8% to 2.4% with an average of 2.0% and the protective rates were 78.4 to 85.2%. 14 years after the program, the cumulative incidence of acute hepatitis B in the children aged 1 to 14 years fell to 1.5 cases per 100,000 children, down 91.8% as compared with that in 1985 to 1987. However, the cumulative incidence of 14.4 cases per 100,000 population in unvaccinated children was not significantly different from that in the history controls. Acute hepatitis B children had not been reported, showing that the vaccination program was 100% protective in children.</p><p><b>CONCLUSION</b>The universal infant HB vaccination program in a hyperendemic area has proved to be effective in controlling HBV infection and decreasing the incidence of acute hepatitis B in children. Booster dose is unnecessary in 13 years after the immunization. The protective efficacy of yeast recombinant HB vaccine is similar to that of plasma-derived HB vaccine.</p>