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.