[Surveillance of adverse events following immunization in Henan Province, China between 2010-2011]

To analyze the epidemiological features of adverse events following immunization (AEFI) in Henan Province, China and to evaluate the safety of vaccines currently used in Henan.

The AEFI cases reported in Henan from January 1, 2010 to December 31, 2011 were collected through the China Surveillance System of Information on National Immunization Program. The descriptive method was used for epidemiological analysis.

A total of 2415 cases of AEFI were reported in Henan from January 1, 2010 to December 31, 2011, and 1238 (51.26%) of them were found in Zhengzhou, Luoyang, and Jiaozuo cities. The male-to-female ratio was 1.32:1. Seven hundred and ninety-nine (33.08%) of these cases were less than one year old. Measles vaccine and DPT vaccine (against diphtheria, pertussis, and tetanus) were the main causes of AEFI, contributing to 61.24% of cases; the incidence rates of AEFI among people receiving measles and DPT vaccines were 30.3/105 and 5.0/105, respectively. 1528 cases (63.27%) developed AEFI after the first dose of vaccination. Inflammation and allergic symptoms were the predominant adverse effects caused by the top 5 vaccines AEFI-causing vaccines, and the clinical manifestations were significantly different among AEFI cases caused by different vaccines (χ2=304.5, P<0.001). Among the 2415 AEFI cases, 1946 (80.58%) had common adverse reaction, 348 (14.41%) had rare adverse reaction, 98 (4.06%) had coupling disease, 13 (0.51%) had psychogenic reaction, and 10 (0.41%) had reaction for unknown reasons. The prognosis of most AEFI cases was good, with a cure rate as high as 90.64%.

AEFI occurs mostly in young children and after the first dose of vaccination. This should be brought to the attention of vaccination service personnel and the children's parents.