[Study on the effects of controlling hepatitis A epidemics by building the colony immune defence].
OBJECTIVE
To build the colony immune defence and to control the periodic epidemics of hepatitis A after a mass vaccination of live attenuated hepatitis A vaccine.


METHODS
Through yearly observing the correlation of the accumulative inoculation rates of live attenuated hepatitis A vaccine, the crowd immune standard and the morbidity of hepatitis A after administered live attenuated hepatitis A vaccine among susceptible population and surveilling anti-HAV IgG in the different epidemic areas.


RESULTS
(1) The accumulative inoculation rates of live attenuated hepatitis A vaccine was 34.15% in 8 years from 1993 to 2000, among which they were 84.46%, 82.23% and 15.14% in the preschool children, primary and middle school student and 15 - 45 age groups respectively. The morbidity of hepatitis A decreased to 8.26/100,000 in 2000. (2) The crowd positive rates of anti-HAV IgG were 74.24% in 1998 and 83.68% by 2000. Among which they were 74.02%, 68.49%, 79.41%, 85.71% and 90.80% in 2 - 4, 6 - 8, 13 - 15, 20- and 30 - 39 age groups respectively. (3) The accumulative inoculation rates were 37.36%, 51.08% and 28.68% in the inspection areas of Tongtai, Binhai and Yandu respectively. The crowd positive rates of anti-HAV IgG in three inspect area were 85.71%, 85.94% and 78.63% respectively. It was noticed the correlation between the accumulative inoculation rates and the crowd positive rates of anti-HAV IgG was (r(city) = 0.91, F = 15.10, P < 0.03).


CONCLUSIONS
The results showed that the crowd positive rates of anti-HAV IgG had increased to 85% while, the colony immune defence of hepatitis A was effectively built to break the periodic epidemics of hepatitis A. The morbidity of hepatitis A decreased to the lowest level in the history.
Chen
Yin-zhong
YZ
Yancheng Municipal Sanitary and Anti-epidemic Station, Jiangsu Province, Yancheng 224002, China.
Jiang
Ren-jie
RJ
Yu
Wen-xiang
WX
Li
Cheng-hui
CH
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D005260:Female; D006506:Hepatitis A / Q000453:epidemiology / Q000517:prevention & control*; D022362:Hepatitis A Vaccines / Q000276:immunology*; D017957:Hepatitis A Virus, Human / Q000276:immunology; D006508:Hepatitis Antibodies / Q000097:blood; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D032541:Mass Vaccination / Q000706:statistics & numerical data; D008875:Middle Aged; D014613:Vaccines, Attenuated / Q000276:immunology
D022362:Hepatitis A Vaccines; D006508:Hepatitis Antibodies; D007074:Immunoglobulin G; D014613:Vaccines, Attenuated