An investigation and analysis on the epidemic of varicella in a university of Weifang in China

Objective To investigate the reasons and understand the epidemiological features of the cluster outbreak of varicella in university, and provide scientific basis for preventing varicella. Methods The cases were diagnosed by clinical manifestations and serological test. An epidemiological survey was carried out using case study questionnaire combined with serological test of close contacts. Results This outbreak lasted 45 days from Oct 15th to Nov 30th, four cases were accumulated involving one major and two classes, with the incidence rate of 3.7% (4/107). All patients were male adult students. The serological test results showed that the VZV-IgM antibody was positive in acute phase sera of 4 patients, and the level of VZV-IgG antibody in the recovery phase sera was 4 times higher than that in the acute phase. One of 45 contacts was VZV-IgM positive while 4of 45 contacts were VZV-IgG positive. Conclusion This cluster varicella epidemic was caused by VZV. Close contact may be the risk factor. The school should strengthen the management of infectious diseases, and strictly enforce the epidemic registration system. Effective isolation measures and publicity works were also needed. Besides, it were promoted that the census of varicella antibodies in healthy population and vaccination.