HAV Epidemiological Survey And Analysis In Yixian County

ObjectiveTo research the epidemic characteristics of patients infected with hepatitis A virus (HAV) in Huangshan City. And to find out the HAV-IgG levels and immune status followed by immunization of HAV vaccine in healthy people in Yixian County. These will be paid foundation to the prevention and control for hepatitis A virus infection.MethodsThe epidemic data of hepatitis A were collected and retrospectively analyzed Huangshan from2004to2011. And the healthy in Yixian County, they was selected using the stratified cluster random sampling method, were surveyed about the demography and the dietary habits, and then the HAV-IgG levels in their serum were detected using the ELISA. Finally, the risk factors for HAV infection were analyzed in the healthy.ResultsThe average annual incidence rate of hepatitis A in Huangshan City was2.00/one hundred thousands from2004to2011. Theincidence rate of Yixian County is highest among other counties, which accounts for is2.39/one hundred thousands. During this study period, the incidence rate decreased from4.71/one hundred thousands of2004to0.66/one hundred thousands of2011. A total of1622subjects were enrolled in the present study with total HAV IgG in926subjects were sero-positive with positivity rate of57.09%. The highest rate of over all anti-hepatitis A antibodies is the6-10age group, with positivity rate of90.98%. the lowest rate is the16-20age group, with positivity rate of10.69%. and the positive rate is more than70%in the group over the20years. Total HAV antibody positivity rates were significantly higher in subjects with HAV vaccination than those without HAV vaccination records,and the antibody level would gradually decreased as time pass by. Poor sanitation and hygiene condition are risk factors for infecting hepatitis A, including unsanitary toilet, drinking unboiled water and low health awareness. The anti-hepatitis A antibody titers is less than1:5in in the group below the20years mostly, and that is about1:40in the group above the20years mostly.ConclusionThe prevention of hepatitis A in Huangshan City has achieved significant effect. The vaccination strategy of hepatitis A in yixian County significantly improve the antibody levels of hepatitis A among child and adolescent. Given the facts that antibody level after natural infection of hepatitis A is higher than the population with hepatitis A vaccine and the hepatitis A antibody titers of one dosage immunization is better than of two dosage, we may consider booster immunization after years of vaccination. High consideration should be paid as the HAV infection rate among healthy population in Yixian County is higher than that of other counties in Huanshan City, especially in the group of20+, of which were passive immunized with hepatitis A. The comprehensive strategy on risk population and transmission interruption should be taken sustainably to strengthen the capacity of hepatitis A control and prevention.