Seroepidemiology of Varicella and value of self-reported history of Varicella infection in Iranian medical students.

OBJECTIVES We conducted this study to assess the seroprevalence of Varicella zoster virus (VZV) antibodies in a group of Iranian medical sciences students that were at risk of Varicella and the value of self-reported history as a predictor of immunity. MATERIAL AND METHODS 255 medical, nursing and obstetrics students who had not entered as a student or worked in a hospital from 3 different schools were enrolled in the study in 2012 (Qazvin province, Iran). Demographics and other information as well as the history of Varicella were obtained through a self-administered questionnaire. Blood samples were collected to determine the Varicella IgG levels via an enzyme-linked immunosorbent assay. A statistical analysis was performed by calculating prevalences and their 95% confidence intervals. Sensitivity, specificity, positive and negative predictive values, Cohen's kappa and positive and negative likelihood ratios of recalled history were determined. p < 0.05 was considered statistically significant. RESULTS The mean age of participants was 21.3 ± 4.3 years. Seropositivity rate was 74.5%. The relationships between marital status, number of family members, and acquired VZV history with immunity against the virus were statistically significant. The overall rate of reported history was 57%. The positive and negative predictive values of self-reported history of Varicella were 91% and 47.3%, respectively. CONCLUSIONS Immunization of students of Iranian medical sciences seems logical in the near future. Also, they should be tested for Varicella immunity regardless of the history of previous infection.