Has Clinical and Epidemiological Varicella Burden Changed over Time in Children? Overview on Hospitalizations, Comorbidities and Costs from 2010 to 2017 in Italy

Abstract

According to WHO estimates, varicella disease is responsible of a worldwide significant burden in terms of hospitalizations, complications, and deaths, with more than 90% of cases under 12 years old. This study aims at evaluating the clinical, epidemiological, and economic burden of varicella in Ligurian children, about comorbidities, organizational variables, and vaccination coverages from 2010 to 2017, in terms of Emergency Department accesses and hospitalizations. The overall hospitalization rate was 179.76 (per 100,000 inhab.), with a gradual but significant decline since 2015, when universal varicella vaccination was introduced in Liguria (p < 0.0001). The risk of being hospitalized for complicated varicella in subjects with at least one comorbidity was significantly higher than in subjects without comorbidities (p = 0.0016). The economic analysis showed higher costs in subjects with complicated varicella who were 0–3 years old. This age group showed higher costs also considering extra-hospital costs for both outpatient procedures and pharmaceutical costs (p < 0.0001). The results confirm the relevant burden of varicella, especially in the 0–3 age group and in children with comorbidities. Thus, vaccination with the achievement of adequate vaccination coverages is confirmed to be a necessary control strategy to reduce hospitalizations and associated complications with important economic benefits.

Impact assessment of immunization and the COVID-19 pandemic on varicella across Europe using digital epidemiology methods: A descriptive study

“…Notably, in Hungary, UVV was introduced in 2019, shortly before the COVID-19 pandemic began, limiting the period of observation to evaluate the effect of UVV under pre-pandemic conditions. This aside, our findings accord with studies from Europe and the United States reporting declines in varicella infections and hospitalization in the years following UVV implementation [ 6 , 7 , 25 , 32 ]. For example, in Germany UVV led to a greater than 50% reduction in varicella cases and a greater than 70% reduction in varicella-associated hospitalizations [ 7 ], while in Veneto, Italy, incident varicella in children fell by 90% following the introduction of a quadrivalent measles-mumps-rubella-varicella vaccine [ 32 ].…”

“…Furthermore, in univariate modeling, reported varicella corresponded well with values predicted using Google Trends data; the model’s adjusted R 2 was 0.75, indicating that Google Trends data account for a sizable proportion of the variability of reported case data ( S3 Fig ). Data on relative search query popularity for varicella keywords also corresponded closely to published reports of monthly varicella-associated hospitalization rates in Italy [ 25 ] and monthly varicella incidence in Croatia [ 23 ] and Sweden [ 24 ].…”

“…Both relative and absolute search query volumes for varicella keywords during the 5 years preceding the COVID-19 pandemic displayed seasonal variation in countries without UVV, peaking in the autumn or winter and in the spring. This pattern aligns with seasonal variation reported in studies of incident varicella infections and varicella-related hospitalizations from several European countries [1,19,[23][24][25][26][27][28][29]. Using data from Bulgaria as a comparator, we quantitatively evaluated clinical varicella incidence with the Google Trends Index, finding an adjusted R 2 value of 0.75.…”

“…We identified 1 study that evaluated the effect of UVV on trends in search queries for varicella keywords which found, as we did, that in countries with UVV, search query intensity displayed moderate to little seasonal variation [ 19 ]. This trend may be explained by the fact that UVV suppresses the transmission and seasonal variation of varicella infections [ 6 , 7 , 19 , 25 ], which subsequently reduces information seeking on varicella.…”

“…To quantitatively evaluate the validation dataset from Bulgaria, we developed a univariate linear model, which regressed reported varicella cases against relative search query volumes. We further validated our analytic approach by empirically evaluating the correspondence between study data and monthly trends in varicella incidence and varicella-associated hospitalizations in published reports from Croatia [ 23 ], Sweden [ 24 ] and Italy [ 25 ].…”