RESUMO
<p><b>OBJECTIVE</b>To investigate the epidemic status of Hepatitis B in children aged 1-14 in 3 counties of Guangdong province in 2013, and to evaluate the effect of hepatitis control in children aged 1-14 after hepatitis B vaccine was integrated into the national immunization program in 2002 and catch-up vaccination was conducted from 2009 to 2011.</p><p><b>METHODS</b>A multi-stage stratified random sampling was designed to survey 1 621 children aged 1-14 in rural area of Nanxiong county, Haifeng county and Xinxing county by questionnaires including general information, medical history and risk factors. The samples were tested with chemiluminescence method to detect hepatitis B virus (HBV) surface antigen (HBsAg), antibody to HbsAg (anti-HBs) and antibody to HBV core antigen (anti-HBc). Chi-square test was used to compare the positive rate of HBV serum markers in different age groups, vaccine histories, birth weight and HBV infection status of mother.</p><p><b>RESULTS</b>Among the children aged 1-14 in 3 counties rural regions of Guangdong province, the positive rate of HBsAg, anti-HBs, and anti-HBc was 1.11% (18/1 621), 60.69% (982/1 618) and 1.92% (31/1 617), respectively. The HBsAg positive rate of vaccinated children (0.84%, 13/1 547) was lower than that of unvaccinated children (1/13) or children with unknown vaccination status (6.56%, 4/61) (χ² = 22.64, P < 0.001). The HBsAg positive rate (0.45%, 5/1 118) of the children with birth-dose given within 24 hours was lower than those that of children given beyond 24 hours (2.63%, 61/190) (χ² = 10.21, P < 0.001). The HBsAg positive rate (5/18) of children with birth weight under 2 kilogram was higher than that of children with birth weight above 2 kilogram (0.78%, 12/1 548) (χ² = 120.8, P < 0.001). The HBsAg positive rate of children born to HBsAg-positive mothers (2.80%, 3/107) was higher than that of children born to HBsAg-negative mothers (0.21%, 1/470) (χ² = 8.50, P = 0.004). With the age increasing, the coverage and timely birth-dose coverage of Hepatitis B vaccine (HepB) decreased, and the positive rate of anti-HBs gradually decreased.</p><p><b>CONCLUSION</b>After the catch-up vaccination was conducted in unvaccinated children aged 1-14 years from 2009 to 2011, the HBsAg and anti-HBc positive rate decreased, while the anti-HBs positive rate increased significantly.</p>