title: Era of vaccination heralds a decline in incidence of hepatitis A in high-risk groups in China.
abstract: BACKGROUND
  Hepatitis A was ranked first among all of the different types of viral hepatitis in China, which occurred an average of 500,000 cases annually during the 1980's. A live attenuated hepatitis A vaccine was applied in preventing of the disease in 1992, large scale used in vaccination program in 1995, and incorporated in the Expanded Program of Immunization in 2008 in China.
  
  
  OBJECTIVE
  The objective of this study was to determine whether, and to what extent, the decline in the incidence of hepatitis A in China was the result of hepatitis A (HA) vaccination.
  
  
  METHODS
  Official documents and longitudinal serological follow-up studies were reviewed to compare the incidence of HA before and after the introduction of the vaccine.
  
  
  RESULTS
  National trends in the incidence of HA in China saw rates decrease by 92.7% in 2009, compared to the levels seen in 1992. A mass vaccination program was carried out in 3-18 year old children (Wuhan City, China), and its protective efficacy was 85.4%. In a mass vaccination program of an entire population (Shenshi County, China), the annual HA incidence decreased from 359.7/100,000 to 17.7/100,000 (almost 20.3 times). There was a significant relationship found between vaccine coverage and the incidence of HA, the correlation of the negative regression was significant at the 1% (Kendall rank correlation, significant level P < 0.05).
  
  
  CONCLUSIONS
  In summary, this study highlights the important role of implementing a vaccination program in decreasing the incidence of HA, and the large protective efficacy of such a strategy, as demonstrated in China.
authors.affiliation: Institute of Viral Disease, Zhejiang Academy of Medical Sciences, Hangzhou, China; Key Lab for Bio-tech Vaccine Research, Hangzhou, China. fczhuang@163.com
authors.forename: Zhuang
authors.initials: Z
authors.lastname: Fangcheng
authors.forename: Wang
authors.initials: W
authors.lastname: Xuanyi
authors.forename: Chen
authors.initials: C
authors.lastname: Mingding
authors.forename: Jiang
authors.initials: J
authors.lastname: Liming
authors.forename: Wu
authors.initials: W
authors.lastname: Jie
authors.forename: Jiang
authors.initials: J
authors.lastname: Qi
authors.forename: Gong
authors.initials: G
authors.lastname: Yuanping
authors.forename: Qian
authors.initials: Q
authors.lastname: Wen
authors.forename: Xin
authors.initials: X
authors.lastname: Yajuan
authors.forename: Mao
authors.initials: M
authors.lastname: Jiangsen