Varicella zoster virus transmission dynamics in Vojvodina, Serbia

Abstract

This study aimed at establishing baseline key epidemiological parameters for varicella zoster virus (VZV) infection in Vojvodina, Serbia, with the ultimate goal to quantify the VZV transmission potential in the population. Seroprevalence data generated during the first large cross-sectional VZV serosurvey were modelled, using a two-tiered modelling approach to calculate age-specific forces of infection (FOI), the basic reproduction number (R0) and herd immunity threshold (H). Seroprevalence and modelling data were compared with corresponding pre-vaccination epidemiological parameters from 11 countries participating in the European Sero-Epidemiology Network 2 (ESEN2) project. Serbia fits into the general dynamic VZV transmission patterns in Europe in the pre-vaccine era, with estimated R0 = 4.12, (95% CI: 2.69–7.07) and H = 0.76 (95% CI: 0.63–0.86). The highest VZV transmission occurs among preschool children, as evidenced by the estimation of the highest FOI (0.22, 95% CI: 0.11–0.34) in the 0.5–4 age group, with a peak FOI of 0.25 at 2.23 years. Seroprevalence was consistently lower in 5–14 year-olds, resulting in considerable shares of VZV-susceptible adolescents (7.3%), and young adults (6%), resembling the situation in a minority of European countries. The obtained key epidemiological parameters showed most intense VZV transmission in preschool children aged <4 years, justifying the consideration of universal childhood immunization in the future. National immunization strategy should consider programs for VZV serologic screening and immunization of susceptible groups, including adolescents and women of reproductive age. This work is an important milestone towards the evaluation of varicella immunization policy options in Serbia.

Sero-epidemiological study in prediction of the risk groups for measles outbreaks in Vojvodina, Serbia

“…The collection of the main serum bank was performed according to the guidelines and specifications of the European Sero-Epidemiology Network 2 (ESEN2) project [18]. Details of the survey design and sampling method have been described previously [19, 20]. In brief, a total of 3199 residual diagnostic sera from participants were collected during inter-epidemic period in Vojvodina, from April 2015 to June 2017 (point of seroprevalence survey).…”

Seroprevalence Study of Anti-HBs Antibodies in the General Population of Vojvodina, Serbia

“…The study protocol followed the specifications and guidelines of the European Sero-Epidemiology Network 2 (ESEN2) project [ 15 ]. The method of recruitment of study participants, i.e., their serum samples, as well as the design and method of this study are described in detail elsewhere [ 16 , 17 ]. In brief, 3467 serum samples were collected in the period between April 2015 and March 2016 as part of a larger serosurvey conducted in order to assess the level of immunity against several vaccine-preventable diseases in Vojvodina’s population.…”

Modeling the transmission dynamics of varicella in Hungary

“…Note that in the literature a wide variety of different R 0 values can be found for the VZV. In [9], the highest value is 16.91 (Netherlands) and the lowest is 3.31 (Italy). Knowing the parameters in these countries, estimation on the underreporting can also be given.…”

“…It is obvious that R 0 is highly sensitive to zoster related parameters, but since no zoster report are available, the uncertainties of their estimates explain the uncertainties of R 0 . See the country-wise difference in [9]. We consider another aspect in the next section.…”