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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.

Background Since the protection time by hepatitis B (HB) vaccination is unclear, the strategy of immunization of junior students who previously received hepatitis vaccine is controversial. Objectives This study aimed to determine the status of immunity to hepatitis B in junior medical, nursing and obstetrics students with different hepatitis B virus (HBV) vaccination patterns. Patients and Methods In an analytical cross-sectional study, 255 junior medical sciences students were tested for quantitative antibodies to hepatitis B surface antigen (anti-HBs). The proportion of protective immunity was compared in different vaccination patterns. Results Vaccination coverage rates were 74.1%. About half the participants didn’t show serological evidence of protective immunity; 68.9% had their last shot more than 10 years ago and 30.4% had a vaccination history of five years or less (P < 0.001). Geometric mean level of anti-HBs titer among students, who had received a primary series vaccine at birth, was significantly lower than students who had started vaccination at an older age (P < 0.001). Also, analysis of variance for geometric mean of anti-HBs titer showed significant differences between groups based on injection time from the last shot (P < 0.001) (post hoc comparisons resulted in a P value of < 0.001 for birth versus < 5 year group, and P < 0.001 for the 5 to 10 year group). The lowest rate of non-protective level belonged to participants with complete three doses and a booster additional shot (27.1%). The final model for independent predictors of anti-HBs positive status was made by a binary logistic regression analysis. The model included presence of a booster dose, injection time from last shot, and discipline of study. Conclusions This study shows lower anti-HBs among students who were vaccinated at infancy compared to those vaccinated at older childhood or adolescence. Also, subsequent measurement of anti-HBs level at the time of entrance to university is recommended for all previously immunized students.