反复呼吸道感染（recurrentrespiratoryinfection,RRI，简称复感）是小儿时期的多发病，尤其常见于3岁以下儿童，往往反复发生上、下呼吸道感染，一年间可至七八次以上。根据我们在北京郊县对农村0～6岁儿童呼吸道感染进行两年监测，年复感发生率为90％及13．2％；在北京市区对 Recurrent respiratory tract infection (recurrent respiratory tract infection, RRI, referred to as re-sense) is a common childhood disease, especially common in children under 3 years of age, often repeated upper and lower respiratory tract infection, up to seven or eight times a year. According to our two-year monitoring of respiratory infections in children aged 0-6 years in suburban Beijing, the incidence of annual recurrent influenza was 90% and 13.2% respectively. In Beijing,