Google Trends Suggests Chickenpox Spread Suppressed During COVID-19
The internet search query data that evaluated trends in varicella incidence in Europe following the introduction of Universal Varicella Vaccination (UVV) suggest that varicella incidence decreased in response to COVID-19 pandemic interventions.
Varicella, commonly referred to as chickenpox, is a highly transmissible infection caused by the varicella-zoster virus. It is usually a mild and self-limiting disease; however, it can lead to serious or fatal outcomes, even in young children, but particularly in newborns, pregnant women, adolescents, adults, and individuals with a weakened immune system.
‘Google search query data used as a proxy for trends in varicella infection revealed that transmission of chickenpox may have been suppressed during the COVID-19 pandemic.’
Data suggest that infection control measures implemented during the COVID-19 pandemic led to altered seasonal variation and marked decreases in incidence for several pediatric infections. However, few studies have evaluated the effects of the COVID-19 pandemic on varicella incidence.
Therefore, a new study published in the journal PLoS ONE assessed Google keyword search queries for varicella as a proxy for trends in varicella infection rates and evaluated the effect of UVV on these trends from 2015-2021.
Effect of the COVID-19 Pandemic on Volume of Search Queries for Varicella Keywords
In the 5 years preceding the COVID-19 pandemic, from 2015 through 2019, the relative search query popularity of varicella keywords displayed pronounced seasonal variation in most countries without UVV.Seasonal peaks in relative search query popularity occurred in the autumn or winter (October to January) and in the spring (March to June). A similar seasonal pattern was observed for the absolute volume of varicella keyword searches in European countries without UVV.
In countries with no UVV, relative search query volumes were markedly lower during the pandemic period compared with values predicted in the absence of the pandemic. Similarly, COVID-19 appeared to have a downward effect on trends in absolute search query volumes.
However, all 28 countries included in the study recorded abrupt and unseasonal declines in the absolute volume of search queries for varicella keywords during April, May, and June 2020, the first 3 months of the COVID-19 pandemic.
These declines were more pronounced in countries without UVV, and in most countries intensified over time, with March to June declines ranging from 33% to 70% in countries with UVV and from 40% to 76% in countries without UVV.
Varicella poses a substantial socioeconomic and quality of life burden, which is currently under-ascertained by conventional approaches to varicella surveillance in many European countries.
Given the close correspondence between trends in search query intensity and those of varicella incidence, search query data may be useful in buttressing conventional varicella surveillance systems or assessing the burden of varicella where surveillance data is absent.
Hence, consideration should be given to using a similar approach to enhance the estimation of varicella incidence, to support the development of good surveillance systems, which are a fundamental component of resilient public health ecosystems.
Source: Eurekalert