[Analysis on the surveillance of adverse events following immunization in China, 2007-2008].

Abstract

Objective: The study is to analyze the occurrence features of Adverse Event Following Immunization (AEFI) in China, and to evaluate the implementation of AEFI surveillance system, the safety of National Immunization Program (NIP) Vaccines and the quality of the immunization services.

Methods: The AEFI data of 2007-2008 were collected through the China Information System and the Children Immunization Information System, which reported before march 25, 2009. The descriptive methodology was used in the study.

Results: 32120 AEFI cases of 2007-2008 were reported, 95.02% were reported from 10 pilot provinces. The ratio of male and female was 1.41:1.77. 53% cases were < OR =1 years old and the cases were occurred more often between april to october. The first three vaccines are DPT, MPV and JREV. 65.85% happened after the 1st and 2nd dose and 75.05% within 1 d after vaccination. The estimat reported incidence of NIP vaccines were 7.99-322.77 per million doses. In the classification of AEFI cases, 79.93% cases were common, minor reactions, 14.65% were rare, serious reactions and others were <5%. Anaphylaxis, sterile abscess and vaccine reaction of BCG were the most common clinical diagnosis. 91.2% AEFI cases were cured or improved. Only 1.93% were hospitalized, among them 2/3 stayed in hospital < or = 10 d.

Conclusions: Comparing with 2005-2006, the completeness and sensitivity of national AEFI surveillance system were improved greatly in 2007-2008, but it still needs to be strengthened. The NIP vaccines were significantly related to the introduced vaccines in Expanded Immunization Program. AEFIs occurrence mostly in young children, first-dose and the early period of vaccination. The pilot study showed that safety of NIP vaccines and the quality of immunization services are satisfied.