Seroepidemiology of varicella-zoster virus antibodies among health-care workers and day-care-centre workers

Inclusion of live varicella vaccine in the routine occupational health vaccination schedule requires knowledge of the natural immunity to varicella zoster virus (VZV) among high-risk occupations. This study aims were to evaluate VZV antibody positivity among health-care workers (HCWs) and day-care-centre workers (DCWs) and to assess its association with potential risk factors. Three groups of workers were tested for VZV antibody positivity: hospitals and community clinic HCWs (n = 335), DCWs (n = 117) and blue-collar workers as controls (n = 121). The total VZV antibody positivity was 94.4%. There was no significant difference in VZV antibody positivity among study groups. DCWs had the lowest VZV seroprevalence (90.9%, 95% CI 85.7-96.1) and controls the highest (96.6%, 95% CI 93.2-99.9). This high VZV antibody positivity suggests that no special occupational measures are indicated in health-care or day-care occupational settings in Israel. On-going monitoring of the natural immunity to VZV is necessary to detect trends over time.