Surveillance on the levels of antibody to pandemic influenza A(H1N1)2009 virus before and after vaccination with pandemic influenza A(H1N1)2009 vaccines in Shanghai middle school students

Abstract

Objective To understand the levels of antibody to pandemic influenza A(H1N1)2009 virus before and after vaccination with pandemic influenza A(H1N1)2009 vaccines in Shanghai middle school students, and to observe the protection of pandemic influenza A(H1N1)2009 vaccines for this group.Methods The levels of antibody to pandemic influenza A(H1N1)2009 virus in Shanghai middle school students were determined using the routine micro-hemagglutination inhibition test in three periods, and the positive rates of the antibodies in three periods were compared by Pearson's x2 test. Results Before the epidemic of pandemic influenza A(H1N1)2009, the positive rate of antibody to pandemic influenza A (H1N1)2009 virus among Shanghai middle school students was only 1.3%, and then it increased to 8.5% after a period of epidemic. After vaccination with pandemic influenza A(H1N1)2009 vaccines, the positive rate of antibody to pandemic influenza A(H1N1)2009 virus among middle school students increased to 87.3%. The result of Pearson' sx2 test showed that differences of the positive rate of antibody in three periods had statistical significance(x2 = 243.7, P ＜ 0. 05). Conclusions Before the epidemic of pandemic influenza A(H1N1)2009, Shanghai middle school students almost have no immunity against this new type of virus, and vaccination with pandemic irfluenza A(H1N1)2009 vaccines can provide stronger protection for this group. Key words: Influenza A virus, H1N1 subtype; Influenza vaccines; Antibodies, viral; Hemagglutination inhibition tests