Serosurveillance of varicella and hepatitis B infection after reported cases in medical students and the relationship between past varicella disease history and immunity status.

OBJECTIVE: To identify seroprevalence of varicella and the relationship with their histories of experiences of varicella diseases and to provide appropriate immunization against varicella, mumps, measles, rubella and hepatitis B to medical students. MATERIAL AND METHOD: All of the medical students were eligible for participation after informed consents. Immunization history against varicella, mumps, measles, rubella (MMR) and hepatitis B were obtained from a questionnaire. A blood sample was obtained from each student for IgG antibody against VZV by ELISA. Medical students with an uncertain history or no documentation of hepatitis B vaccination were tested for HBsAg and anti-HBcIgG by ELISA. RESULTS: There were 383 medical students enrolled. The mean age at enrollment was 21.6 years (median 21.4 years; range 18-25.8 years). Of 383 medical students, 372 (97.2%) had documents of receiving MMR immunizations. The blood samples were obtained from 374 of 383 (97.6%) medical students to identify the immunity against varicella zoster virus (VZV) and the seroprevalence rate was 92%. Using VZVIgG antibody detection as a standard test, history of experience of varicella disease provided positive predictive value of 99.3% (148/149). Of 383 medical students, 277 (72.3%) were tested for hepatitis B markers and 243 (87.7%) students showed negative results. The prevalence of HBsAg carriers was 0.01% (4/383). CONCLUSION: Suboptimal immunities against vaccine preventable diseases could be demonstrated in the medical students including varicella and hepatitis B. New recommendations of immunizations against varicella, MMR and hepatitis B viruses for a particular group of the population were provided.