Spatiotemporal distribution of varicella in the Republic of Korea

Abstract

Varicella is a highly contagious disease caused by the varicella-zoster virus (VZV).Given its tendency to cluster geographically, spatial analyses may provide a better understanding of the pattern of varicella transmission. We investigated the spatial characteristics of varicella in Korea and the risk factors for varicella at a national level. Using national surveillance and demographic data, we examined the spatial distribution of incidence rates and their spatial autocorrelation and calculated Moran's index. Spatial regression analysis was used to identify sociodemographic predictors of varicella incidence at the district level. An increasing tendency in the annual incidence of varicella was observed over a 12-year period (2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018), with a surge in 2017. There was a clear positive spatial autocorrelation of the varicella incidence rate during the surveillance period. During 2006-2014 clusters were mostly confined to the northeast region and neighboring districts. The spatial error model showed that population density had a negative coefficient and childhood percentage, percentage of children under 12 years of age among the total population, had positive coefficient, whereas vaccine coverage was insignificant. The varicella incidence according to geographic region varied with population density, childhood percentage, suggesting the importance of community-level surveillance and monitoring strategies.

Epidemiological Characteristics of Varicella in Anhui Province, China, 2012-2021: Surveillance Study

“…Varicella showed a seasonal rise in winter and summer, which was consistent with previous studies [19,21]. In 2020, the incidence of varicella significantly declined and only a predominate winter peak occurred; this phenomenon has also been observed for other respiratory infectious diseases.…”

“…Although spatiotemporal clusters of varicella have occurred in the cities of Bengbu, Huaibei, and Fuyang in the northern region of Anhui from 2017 to 2021, on the whole, the reported incidence in southern Anhui was higher than that in northern Anhui. Several studies found that respiratory infectious diseases showed patterns of high-risk clusters in remote rural or urban-rural transition zones where economic, educational, and medical resources are often lacking [21,42,43]. However, the most likely clusters of varicella in Anhui were located in the more economically developed areas of Hefei and in the southeast region of the province.…”

“…Spatiotemporal investigations based on geographic information systems have been increasingly used in modern epidemiology research [20], which could help to visualize the incidence trends and spatial distributions of infectious diseases, providing a new framework for analyzing their spatiotemporal changes and transmission patterns. Previous studies demonstrated the spatiotemporal aggregation and spatial correlation patterns of varicella occurrence [19,21]. However, no study has yet focused on the epidemiological characteristics or spatial and temporal distributions of varicella in Anhui.…”

Epidemiological characteristics of varicella outbreaks in the Republic of Korea, 2016–2020

“…From 2016 to 2018, the number of varicella outbreaks increased, after which it slightly decreased in 2019 and then fell sharply in 2020, when the coronavirus disease 2019 (COVID-19) pandemic occurred. Lee et al [ 22 ] analyzed NIDSS data from 2006 to 2018. In another study conducted by Lee et al [ 14 ], the data were analyzed from 2006 to 2017.…”