| BackgroundIt is wellknown that Bacille Calmette-Guerin vaccine(BCG) has a documented effect against meningitis and dissemniated Tuberculosis in Children and it has the widest use over the world till today.ln China, it has been vaccinated to over hundreds of millions of babies since 1978 as one of the government-paid vaccines(Catogory I vaccine). Post-marketing surveillance of Adverse Event Following Immunization(AEFI) in a large population is an important method to know and assess the safety profile of BCG, but in China, few large-scale saftety study of BCG vaccination has ever been conducted. Under the circumstances that many western countries started to stop routine BCG vaccination to children and BCG is only recommended to highly risky population and shortage of safety profile of BCG vaccination in China, it is significant to take advantage of China AEFI surveillance system to collect AEFIs of BCG and to analyze the safety of this vaccine, in order to deeply understand and evaluate the safety of BCG vaccines so as to serve as a scientific data for the evaluation of BCG vaccine quality and the formulation of future immunization policy.ObjectiveThis study is to analyze features of BCG AEFIs, especially Serious Adverse Reactions(SAR), including reporting rates, AEFI classification, sex/age allocation, recovery status, onset time interval,and aggregated SARs,etc, from 9 provinces in 2009 so as to evaluate the safety of BCG vaccination.MethodsThrough National AEFI surveillance system, AEFI cases vaccinated during January 1,2009 to Dec.31,2009 were collecte, and from "Children vaccination information management system", actual dosage of BCG vaccinated in these provinces in 2009 are collected, then a descriptive epidemiological method is adopted to analyze the incidence rate and other feature of BCG AEFI in 2009.ResultsIn 2009, totally 559 cases of advese events are collected following the immunization of 6,461,116 doses of BCG in 9 provinces through the National AEFI surveillance system and overall reporting rate of BCG AEFIs is 86.52/1,000,000 and it shows a continuous rise of reporting rate from 2005 to 2009.Of the 559 reporting cases,134(reporting rate:20.89/1,000,000) were verified as Common/Minor Vaccine Reactions,393(reporting rate:60.83/1,000,000)were verified as Rare Vaccine Reactions, 18(reporting rate:2.79/1,000,000) were verified as Program Error,13(reporting rate:2.01/1,000,000) were verified as Coincidental Event.There is no vaccine quality accident or Psychogenic Reaction.Of the 393 Rare Vaccine Reactions,360 cases were suppurative lymphadenitis(reporting rate:55.72/1,000,000),70 were BCG abscess(reporting rate:10.83/1,000,000),27 were allergic rash(reporting rate:4.18/1,000,000),2 were disseminated BCG infection (reporting rate:0.31/1,000,000),1 convulsion and 1 Angioedema(both reporting rate:0.15/1,000,000). SAR allocation by Age:Of 475 SAR cases,462 cases(97.26%) were≤5-month-old(95.15% were 0-2month-old),13 cases(2.74%) were 6-12-month-old and age unknown.SAR allocation by Sex:Of 475 SAR cases,315 (66.31%) were male and 159(33.47%) were female and 1 cases with sex unreported. Reporting rates ratio in male and female:1.65:1。Outcome of SARs:Of 475 SAR cases,236(49.68%) were reported as'improvement'and 186(39.16%) were cured,5(1.05%) with sequeala and outcomes of 48(10.11%) were reported as unknown. No SAR case were death case. Of 559 AEFIs, there were 7 death cases which were all coincidental events.SAR allocation with reporting area:reporting rate among 9 provinces differs with top reporter Guangxi province(184,214.23/1,000,000) and lowest reporter Gansu province(8, 28.21/1,000,000).Interval from BCG vaccination to SAR Onset:Of 475 SARs,48 cases(10.11%) happened within 6d following BCG immunization, mainly high fever, convulsion and allergic reactions; 19 cases(4%) happened during 7-28d, mainly BCG Abscess and some allergic reactions; 234 cases (49.26%) happened during 29d-90d, mainly suppurative lymphadenitis and disseminated BCG infection; 150 cases(31.58%) happened during 91-180d, mainly suppurative lymphadenitis and BCG Abscess;24 cases(5.05%) happened during 181-365d, SARs same as those during 91-180d.Cluster BCG SARs:For manufacturer A,189 SAR cases were reported relating to 40 cluster SARs of its BCG product. Cluster SAR case reporting rate is 113.69 cases/1,000,000, Cluster SAR clusters of its product and reporting rate is 15.11 clusters/1,000,000; For manufacturer B,69 SAR cases were reported relating to 21 cluster SARs of its product; Cluster SAR case reporting rate is 44.05/1,000,000, the aggregated SAR cluster reporting rate is 5.51/1,000,000. It shows the vaccine quality of two BCG manufacturers differs.ConclusionsThis study shows the safety of domestic BCG vaccine is acceptable with SAR reporting rate of 73.56/1,000,000 and main SARs are suppurative lymphadenitis and BCG abscess. SAR reporting rate is higher in male than female. Most SARs happen during 29-180d and most SARs recover well. Cluster SARs for certain batches of two BCG manufacturers exist and shows the vaccine quality is a lot different. Stronger measures have to adopted to avoid BCG program errors.Although the 9 provinces we chose have shown their good sensitivities in AEFI surveillance, the reporting rate among the 9 provinces are different. This study is conducted by collecting and analyzing passive AEFI surveillance data and the real safety of BCG vaccine is to be found out by further clinical studies. |
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