Influence of Pre-vaccination Antibody Titer on Immunogenicity of Influenza A H_1N_1 Vaccine

Objective To assess the influence of pre-vaccination antibody titer on immunogenicity of the influenza A H1N1 vaccine,to provide reference of vaccine immunogenicity strategies.Methods The data in clinic trial of the influenza A H1N1 vaccine were analyzed.To find the influence of pre-vaccination antibody titer of vaccine immunogenicity.Results 5901 participants were enrolled in the trials and received 15μg split-virus vaccine without aluminium adjuvant.At base line,the hemagglutination inhibition antibody titer was lower than other reports at the baseline data.The seroconversion rate reduced in the participants who had high antibody titre on the day 0.The study showed that all vaccine were immunogenic.The antibody titer at pre-vaccination has no relationship to seroprotection rate after first dose vaccination.Conclusion Further researches were needed to find the influence of pre-vaccination antibody titer on the seroconversion rate.There was no need to consider the antibody titer on day 0 before the vaccination.During the influenza A H1N1 pandemic,whole population were suggested to receive the vaccine to increase the seroprotection rate.