Ambispective epidemiological observational study of varicella-zoster virus infection: An 18 year-single-center Bulgarian experience

Abstract

BACKGROUND Varicella (chickenpox) and herpes zoster (shingles) are outcomes of varicella-zoster virus (VZV) infection, and understanding their incidence trends is vital for public health planning. AIM To conduct an ambispective epidemiological study by analyzing the main epidemiological characteristics of VZV infection during an 18 year-period (2000-2018). METHODS We used descriptive and epidemiological methods to characterize chickenpox in Bulgaria, the city of Plovdiv and the region for a period of 18 years (2000-2018). RESULTS The average incidence of varicella-zoster infection for the period 2000–2018 in the Plovdiv region was estimated at 449.58‰. The highest relative share of the infection was assessed in the month of January at 13.6%, and the lowest in the months of August and September at 2.9% (both months). The age group most affected by the infection was 1-4 years, followed by 5-9 years. This corresponds to the so-called "pro-epidemic population" - a phenomenon typical for airborne infections, confirming their mass impact on the perpetuation of VZV infection. CONCLUSION Our findings reveal significant insights into VZV epidemiology, including age-specific incidence rates, clinical manifestations, and vaccination impact. This comprehensive analysis contributes to the broader understanding of VZV infection dynamics and may inform evidence-based preventive measures.