Immune response to one booster dose of inactivated hepatitis A vaccine in college students / 中华流行病学杂志

ABSTRACT

Objective To evaluate the safety and immunogenicity of one booster dose of inactivated hepatitis A vaccine in young adults.Methods The subjects were selected from participants in the clinical trial of immunogenicity of inactivated and attenuated live hepatitis A vaccine in young adults.Eligible subjects were those who had received one dose of inactivated or attenuated hepatitis A vaccine,could be contacted and were sero-negative before primary vaccination.All qualified subjects were immunized with one booster dose of inactivated hepatitis A vaccine.The blood samples were collected before booster dose vaccination and 28 days after the immunization.Anti-HAV antibody titer ≥20 mIU/ml was considered to be sero-protected against hepatitis A virus.Results The GMCs in the inactivated HAV vaccine group and attenuated live vaccine group before booster dose vaccination were 70.80 mIU/ml and 50.12 mIU/ml,respectively,and the sero-protection rates were 94.7％ and 65.0％,respectively.After the vaccination of the booster dose,the sero-protection rates in both groups were 100.0％,and the GMCs were 2 816.09 mIU/ml and 2 654.55 mIU/ml,respectively.Conclusion The GMCs and sero-protection rates of anti-HAV antibody in young adults declined after three years of the primary vaccination.However,the higher GMC and sero-protection rate were observed in the inactivated vaccine group than in the attenuated live vaccine group.Significant increases of GMC levels were observed in both groups after one booster dose vaccination.