Efficacy of emergency vaccination of inactivated hepatitis A vaccine

Objective　The study was conducted to detect the hepatitis A virus antibody (Anti HAV) levels in general population during the hepatitis A epidemic, evaluate the efficacy of emergency vaccination of inactivated Hepatitis A vaccine. Methods　Epidemiological survey was conducted among hepatitis A patients and close contacts, anti HAV level detection was performed in the population, and the emergency vaccination of inactivated hepatitis A vaccine was implemented. 3365 students received the vaccination directly in school and 108 close contacts of hepatitis A patients were vaccinated after screening to assess the safety of vaccines, antibody response over time and protective efficacy of emergency vaccination. Results　The overall positive rates of anti HAV in the population reached 77.82% during the epidemic period. The protection rate of the vaccine among the students and close contacts vaccinated reached 100.00% .The proportion of hepatitis A case of 20 age group declined from 38.89% before the vaccination to 19.44% two months later after the vaccination, and the positive conversion rate of anti HAV among the close contacts reached 80.00% four weeks later after the vaccination. Conclusion Inactivated hepatitis A vaccine is safe and quick to produce protective antibodies after emergency vaccination. Therefore, it can be used to control HAV infection during the hepatitis A epidemic.