Changing Epidemiological Characteristics of Hepatitis A in Zhejiang Province, China: Increased Susceptibility in Adults.
BACKGROUND
Hepatitis A is a common acute hepatitis caused by hepatitis A virus (HAV). Annually, it affects 1.4 million people worldwide. Between 1991 and 1994, HAV infections were highly endemic in Zhejiang Province (China), with 78,720 reported HAV infections per year. Hepatitis A vaccine came on the market in 1995 and was implemented for voluntary immunization. Since 2008, hepatitis A vaccine has been integrated into the national childhood routine immunization program.


OBJECTIVE
To understand the current epidemiological profile of hepatitis A in Zhejiang Province since hepatitis A vaccine has been available for nearly two decades.


METHODS
This study used the 2005-2014 National Notifiable Diseases Reporting System data to evaluate the incidence rate of notified hepatitis A cases in Zhejiang Province.


RESULTS
The overall trend of incidence rate of notified hepatitis A cases significantly decreased from 2005 to 2014 (P< 0.001). During the study period, the reported incidence rate in individuals aged ≤19 years declined to the historically lowest record in 2014. Compared with individuals aged ≤19 years, those aged ≥20 years showed the highest incidence rate (P< 0.001). Majority of HAV infected cases were Laborers, accounting for approximately 70% of reported cases.


CONCLUSIONS
Childhood immunization strategy with hepatitis A vaccine seemed to be effective in decreasing notified hepatitis A incidence rate in individuals aged ≤19 years. Those aged ≥20 years were observed to be the most susceptible population. The vast majority of hepatitis A cases were notified among Laborers. Therefore, we strongly suggest that future preventive and control measures should focus more on adults, particularly Laborers, in addition to the current childhood hepatitis A vaccination programme.
Department of Immunization Programme, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang Province, PR China.
Zhifang
Z
Wang
Department of Immunization Programme, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang Province, PR China.
Yaping
Y
Chen
Department of Immunization Programme, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang Province, PR China.
Shuyun
S
Xie
Department of Immunization Programme, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang Province, PR China.
Huakun
H
Lv
D000328:Adult; D002681:China / Q000453:epidemiology; D004198:Disease Susceptibility / Q000453:epidemiology* / Q000276:immunology; D005260:Female; D006506:Hepatitis A / Q000453:epidemiology* / Q000276:immunology; D022362:Hepatitis A Vaccines / Q000276:immunology; D030041:Hepatitis A virus / Q000276:immunology; D006801:Humans; D007114:Immunization / Q000379:methods; D017589:Immunization Programs / Q000379:methods; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D014611:Vaccination / Q000379:methods; D015164:Vaccines, Inactivated / Q000276:immunology; D055815:Young Adult
D022362:Hepatitis A Vaccines; D015164:Vaccines, Inactivated