Analysis On Post-marketing Immunization Safety Of The Pandemic (H1N1) 2009 Vaccine

Background:Post-marketing surveillance of Adverse Events Following Immunization(AEFI)is crucial in evaluating the safety of vaccines against the pandemic (H1N1)2009 virus outside of the clinical trials. since September 21,2009, Chinese began to vaccination as well as monitoring the AEFI and Vaccinated cases.This study analyzed the data from the post-marketing surveillance from Beijing, Hebei,Shanghai, Jiangsu,Gansu, Guangxi,Hubei provinces to evaluate the safety of the pandemic (H1N1)2009 vaccine.Objective:This study is to analyze the occurrence feature of the pandemic (H1N1)2009 vaccine and to evaluate the immunization safety related to this vaccine in 7 provinces of china.Methods:Through National AEFI Surveillance System,AEFI cases vaccinated during September 21,2009 to March 1,2010 were collected. Vaccination cases vaccinated during the same period were collected by "Children vaccination information management system".Those information were analyzed using descriptive methodology.Results:In total,2372 AEFI cases were reported between September 21, 2009 and March 1,2010 in 7 provinces,with an overall reporting rate of 126.5 per million Dose administered. Of the reported cases,1992(83.98%) were verified as adverse events(reporting rate:106.3 per million). 746 were verified as Serious Adverse Reaction (SAR, reported rate:39.8 per million).SAR includes:Fever(≥38.6℃)(429cases,22.9 per million), Local Reaction(>5.0cm)(16 cases,0.9 per million),Allergic reactions(292 cases,15.6 per million),Febrile convulsion (7 cases,0.4 per million),Brachial neuritis(2 cases,0.1 per million).Analysis on the SAR with Age, Sex, Occupation, Provinces,Manufacturer and Cluster shows:According to the gender anylysis the total reporting rate of SAR is higher in famale, but rate of Fever(≥38.6℃)and Febrile convulsion is lower.The reporting rate of SAR decreased with age.Reporting rate of Hench-schonlein purpura at the age of 5-14 is the highest;febrile convulsion happened at the age of 5～14, the proportion of Fever(≥38.6℃)decreased with age, while allergic reactions increase with age. According to the Occupation anylysis,Children's SAR reporting rate is the highest, followed by Medical staff, Student and Teacher. Most reactions in Medical staff are allergic reactions.According to the provinces analysis,serious reaction reporting rate in Jiangsu is the highest,followed by Beijing, Hebei,Shanghai,Guangxi,Gansu and Hubei. According to the analysis of Manufacturer, SAR reporting rate of C is the highest,followed by E, A, G and D. through standarding the reporting rate of SAR by group of age, the results shows that the reported rate of SAR from high to low is:C>G>E>A>B>D>F. Cluster analysis shows that C and E's Cluster reporting rate is the higher than the other manufacturers. Of the allergic reaction, the median interval of Anaphylactic shock was 15 minutes (range:2-30) after vaccination, and 30 minutes(range:5～645) for anaphylactic laryngeal edema.Three deaths (reporting rate:0.2 per million) were reported after vaccination:one don't exclude cardiac death;autopsy showed that one case had serious pre-existing heart disease;one had coronary heart disease and long history of medicine.Four AEFI were classified as having unknown etiology,including two cases of Guillain-Barre syndrome (GBS) (reported rate 0.1 per million),one cases of multiple neuritis and one cases of seizure.Conclusion:The pandemic (H1N1)2009 vaccine has good immunization safety. The reporting rate of AEFI and SAR are low. There was no evidence showing abnormally high rate of GBS or any other SAR in the vaccinated population. The reported rate of SAR decrease with age,but higher in Female and in Children, Medical staff and Students.The reporting rate of SAR and Cluster rate are both higher in E and C, Though the reporting rate of SAR is higher in F, the Cluster rate is not high.