Seroprevalence of varicella-zoster virus in Polish population.

A varicella zoster virus (VZV) is the first herpesvirus for which a vaccine was developed. Since 1999, the varicella vaccine is licensed in Poland and recommended for use in adults without history of a varicella infection, and in children and young adults with remission of acute leukemia. While serological data is essential to assess the appropriate vaccination programme, we conducted the first in Poland serosurvey on a representative group of Polish population aged 1-19. Serum samples were selected from a serum bank collected in 1995-2004 with a catchment area of the all geographical regions of Poland. A total of 1300 serum samples collected over 9 years (1995-1996, 1998-2004) were selected using a stratified sampling design (stratification by age). Samples were selected, consisting of 100 samples for each 1-year band of age groups 0-9 years, and 40 samples for each 1-year band of age groups 10-19 years. IgG serum antibodies specific to VZV were detected using an indirect enzyme immunoassay and the antibody level was expressed in international units per millilitre (mIU/ml) and was refered to the international standard for VZV immunoglobulin of 50 IU. The overall seroprevalence estimate, adjusted for sampling design for the age group 1-19 was 76.6% (95% CI: 74.6%-78.7%). Seroprevalence correlated closely with age (p<0.0001) and among 18 and 19 year olds reached 95% and 98% respectively. No association was found between gender, rural/urban areas and geographical regions of Poland. For samples collected over the 5 year period (2000-2004), evidence of overall differences in seropositivity over these years was not observed. In Poland VZV vaccination is provided only for a limited group of high risk patients. The possible updates in the immunization program are discussed and the results of the presented study can contribute valuable information to base the vaccination policy decisions.