| Background and purposeViral hepatitis A widely spreads all over the world.According to the data released by the World Health Organization in 2012,about 1.5 million cases of hepatitis A occurred annually,China was once a high incidence area of viral hepatitis A.The average annual incidence of viral hepatitis A reached 46.02/100,000 in 1990-1994.With the progress of society,the development of economy and the improvement of sanitary environment in China,the incidence of hepatitis A reported declined from 5569/100,000 in 1990 to 166/100,000 in 2015 after the popularization and use of hepatitis A vaccine.Our country has become a moderate epidemic area of hepatitis A from a high epidemic area.However,the prevalence of hepatitis A may still exist and even outbreak with the reduction of natural infection rate and the accumulation of susceptible population.According to the reports,the level of socio-economic development,and the sanitary conditions of living such as diet and drinking can directly affect the incidence of viral hepatitis A.The study on the correlation between vaccination and the incidence of hepatitis A is common.However,it is relatively rare to analyze the correlation between the incidence of hepatitis A and the specific socio-economic development indicators such as per capita GDP,per capita disposable income.Through retrospective analysis of the epidemic data of hepatitis A in Huzhou from 1998 to 2017,this study tried to analyze the effect of the economic and social development level and hepatitis A vaccination on the incidence of hepatitis A in Huzhou.This study compared the epidemic characteristics of viral hepatitis A in Huzhou between 1998-2007 and 2008-2017,and further probed the mainly influenced factors of the prevalence of viral hepatitis A in Huzhou.Materials and methodsThe population data,the per capita gross national product and the per capita disposable income source of Huzhou from 1998 to 2017 are from Huzhou Statistical Yearbook.The data of hepatitis A cases is from Huzhou Infectious Disease Yearbook and Infectious Disease Report Information Management System.The vaccination data is from Huzhou Children's Vaccination Information Management System.The annual incidence rate,age specific incidence rate and sex incidence rate were analyzed.And the incidence of hepatitis A in 1998-2017,1998-2007 and 2008-2017 were calculated by time,region and population.Then regional incidence ratio,sex incidence ratio,age group incidence ratio,and 95%confidence intervals(95%CI)were further calculated.The differences were analyzed by the U test of Poisson distribution.The correlation between incidence of hepatitis A and per capita gross national product(GDP),per capita disposable income and vaccination coverage were studied using the Spearman rank correlation analysis,because that data did not conform to normal distribution.And the differences were statistically significant(P<0.05).ResultsA total of 3194 cases of hepatitis A were reported in Huzhou from 1998 to 2017,with an average annual incidence of 576/100,000.The highest incidence was 2478/100,000 in 1999,and the lowest was 0.82/100,000 in 2015.The incidence of viral hepatitis A from 1998 to 2017 in Huzhou was decreasing year by year.The average annual incidence rate was 10.23/100,000 in 1998-2007,and was 1.72/100,000 in 2008-2017,whose ratio was 5.94(95%CI:5.402-6.536)and meant there was a significant difference between them(P<0.05).The number of cases of hepatitis A had no obviously seasonal peak in the whole year,and more cases appeared during January to April.The Cases mainly occurred in months from January to April in 1998-2007,and however in months from July to October in 2008-2017.The seasonal fluctuation was flatter than that in the first 10 years.The annual average incidence of viral hepatitis A in the counties of Huzhou demonstrated a downward trend from 1998 to 2017.Since 2012 the incidence rates of all counties of Huzhou were at a low level,which is maintained at 2/10 million or less.The average annual incidence of viral hepatitis A in Huzhou from 1998 to 2017 was 7.34/100,000 in males and 4.12/100,000 in females.The ratio of sex incidence was 1.78(95%CI:1.654-1.913),and the difference was statistically significant(P<0.05).The incidence of viral hepatitis A decreased in all age groups in 2008-2017,compared to that in 1998-2007.The annual incidence rate of the group aged 30-44(13.50/10 million)was higher than that of the group aged 45-59(11.07/10 million)in 1998-2007.The ratio of incidence was 1.22(95%CI:1.102-1.349),and the difference was statistically significant(P<0.05).However,there was no significant difference in 2008-2017 between the average annual morbidities of the group aged 30-44(2.13/100,000)and aged 45-59(2.23/100,000),since their ratio was 0.96(95%CI:0.766-1.192).There was no case reported in group aged less than 15 after 2015.The average annual incidence of hepatitis A was negatively correlated with the change of per capita GDP in Huzhou from 1998 to 2017(r =-0.946,P<0.001).The average annual incidence of hepatitis A was negatively correlated with the change of per capita disposable income in Huzhou(r=-0.841,P<0.001).The average annual incidence of hepatitis A in Huzhou was negatively correlated with the change of per capita disposable income of rural households from 1998 to 2017(r=-0.946,P<0.001).And there was a negative correlation between the change of hepatitis A from 1998 to 2017 with an annual incidence of vaccine inoculation in Huzhou(r=-0.941,P<0.001).ConclusionThe incidence of viral hepatitis A from 1998 to 2017 demonstrated a downward trend in Huzhou.With the increasing of population GDP,per capita disposable income of urban and rural households,and the promotion of the use of vaccines,the incidence of viral hepatitis A decreased year by year.The epidemic characteristics of viral hepatitis A have also changed these years.The peak of number of seasonal cases changed from March in 1999-2007 to August in 2008-2017.The regional differences in the incidence shrunk gradually,and the differences in the incidence between men and women as well.The peak age of onset age group moved from 30-44 years old group to 45-59 year old group.The decreasing of the incidence rate of hepatitis A among the groups aged less than 15 was faster than that of the whole population. |
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