Original Articles
Copyright ©The Author(s) 1999. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Apr 15, 1999; 5(2): 122-124
Published online Apr 15, 1999. doi: 10.3748/wjg.v5.i2.122
Long-term effectiveness of infancy low-dose hepatitis B vaccine immunization in Zhuang minority area in China
Hui Li, Rong-Cheng Li, Su-Su Liao, Jian Gong, Xian-Jia Zeng, Yan-Ping Li
Hui Li, Su-Su Liao, Xian-Jia Zeng, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing 100005, China
Rong-Cheng Li, Jian Gong, Yan-Ping Li, Guangxi Anti-Epidemic & Hygiene Center, Nanning 530021, Guangxi Zhuang Autonomous Region, China
Hui Li, M.D., M.P.H., male, born on 1943-06-20 in Jiangjin C ounty, Sichuan Province, China, Han nationality, graduated from Beijing Medical University as a graduate in 1970 and from Peking Union Medical College as a postgraduate in 1982, now professor of epidemiology, majoring hepatitis B control and etiology of cardiological vascular diseases, having 28 papers and 7 books published.
Author contributions: All authors contributed equally to the work.
Correspondence to: Prof. Hui Li, Department of Epidemiology, Ins titute of Basic Medical Sciences, CAMS & PUMC, 5# Dong Dan San Tiao, Beijing 100005, China
Telephone: +86-10-65296971(O) +86-10-65141591(H)
Received: February 5, 1999
Revised: February 21, 1999
Accepted: February 27, 1999
Published online: April 15, 1999
Abstract

AIM To observe the long-term effectiveness of low-dose immunization strategy and risk factors of HBsAg carriers in immunized children of Zhuang minorities of Longan County in the 9th year after infancy immunization.

METHODS Two epidemiologic methods, a cross sectional follow up study and a case-control study, were used for the evaluation of the serological effect and the determination of the risk factors. Hepatitis B virus markers were detected with radioimmunoassay.

RESULTS The protective anti-HBs-positive rate was 43.8% in 1183 children aged 1-9 years, who were immunized with three doses of 10 μg hepatitis B vaccine in infancy according to 0, 1 and 6 months schedule. It declined from 87.9% in the first year to 37.1% in the 9th year after vaccination. The HBsAg-positive rate was 1.6%, not increasing with age during 9 years after the infant immunization program. Compared with 14.0% of HBsAg-positive rate of the baseline survey in 1985, the effectiveness of hepatitis B vaccine immunization was 88.6%. Of 36 immunized children with positive HBsAg, 89.1% were likely attributable to HBsAg positivity of their mothers.

CONCLUSION The long-term effectiveness of infancy low-dose hepatitis B vaccine immunization is high, and the booster is not needed 9 years after the vaccination in the Zhuang minority area where hepatitis B is highly endemic. A high-dose immunization strategy should be recommended in order to further decrease the current HBsAg-positive rate.

Keywords: hepatitis B vaccine; immunization; HBsAg; risk factor