Influencing factors for first cases of varicella aggregation outbreaks in primary school in Pudong New Area of Shanghai

ObjectiveTo investigate influencing factors of the first cases of varicella outbreaks in primary school in Pudong New Area of Shanghai and to provide scientific evidence for effective prevention and control measures against it.

MethodsThe first 80 cases of varicella outbreaks in primary school in Pudong New Area were included for the case-control study.Immunization history, outing activities and information of out-of-school training were gathered.Univariate and multivariate conditional logistic regression analysis were adopted for data analysis.

ResultsMultivariate analysis revealed that varicella vaccination period(OR=0.08, 95%CI:0.01-0.44)was the protective factor for the first case in a varicella outbreak, while weekly frequency of visits to large commercial/supermarkets (OR=4.79, 95%CI:1.86-12.34)and weekly attendance at out-of-school training(OR=1.84, 95%CI:1.01-3.35)were risk factors of the disease.

ConclusionIt is important to promote the current varicella vaccine immunization strategy, to strengthen the disinfection and health education of large commercial/supermarkets and to strengthen infectious disease management, disease prevention guidance and supervision in out-of-school training institutions.