Immunity to varicella-zoster virus in Croatian women of reproductive age targeted for serology testing

The aim of this study was to determine the immunity to varicella-zoster virus (VZV) in Croatian pregnant and non-pregnant women of reproductive age. During 2007-2011, a total of 638 women aged 16-45 years were tested for the presence of VZV IgM and IgG antibodies using commercial enzyme-linked immunosorbent assay. Samples positive for IgG antibodies with positive or equivocal IgM antibodies were tested for IgG avidity. The overall IgG seroprevalence was 84.3 %. There was a significant increase in IgG seropositivity with age (OR = 1.04 for 1-year increase in age; 95 % CI 1.01-1.08). The lowest seroprevalence rate was reported in the 16-20 age groups (78.6 %), and the highest was in the 41-45 age groups (94.3 %). There was no significant difference in seroprevalence among women residing in urban and rural areas (83.6 vs. 87.0 %, OR 0.76, 95 % CI 0.43-1.34). The results of this study have shown that a high proportion of Croatian childbearing-aged women (15.7 %) who were referred to the laboratory for VZV serology testing are susceptible to VZV and, thus, at risk for contracting varicella during pregnancy. Serology testing of adolescent girls and adult women who do not have a documented history of varicella is encouraged with the aim of vaccinating seronegative girls and women against VZV before pregnancy. In addition, testing of pregnant women is advised to identify susceptible women and vaccinate them after delivery.