Google Trends (GT) is an online data tool that measures Relative Search Volume (RSV). In medical settings, it has proven to be associated with patient´s perceptions and even changes in search for medical care. To identify a possible increase in online search patterns about flu vaccination during the COVID-19 pandemic, we conducted a GT analysis in a group of European countries.A GT analysis with the GT topic ‘flu vaccine’ was performed between 2016 and 2020. Retrieved RSV was represented between 0 and 100 (highest interest in the query). Two groups of countries were selected, according to the reported incidence rate of COVID-19 by the European Center for Disease Prevention and Control, between week 37 and 41 of 2020, in children under 15 years (highest incidence: Belgium, Czech Republic, Spain, Portugal and Denmark;lowest incidence: Poland, Sweden, Norway, Finland and Greece).Flu vaccination season (FVS) is considered to be, yearly, between week 38 and 44 and COVID-19 pandemic (CVP) from week 4 of 2020, as the first reported case in Europe was diagnosed.Median RSV about ‘flu vaccine’, before the COVID-19 pandemic, varied between 0 (Czech Republic and Portugal) and 4 (Belgium and Poland) outside the FVS and between 0 (Czech Republic) and 31 (Greece) during the FVS.As the CVP settled, the online search increased significantly, outside the FVS in every country (p<0.05), except in Czech Republic (p=0.216). During the FVS, the search patterns also increased in every studied country (p<0.05), but not in Finland (p=0.214).As to the percentage of increase in RVS (during the FVS), before and during the CVP, the top 5 countries were, in order: Czech Republic (>5200%), Spain (484,6%), Poland (400,0%), Denmark (311,8%) and Portugal (280%). Belgium placed ninth in increase rate, with 149,0%.Flu vaccination is one of the most acknowledged public health measures, and its online search interest usually peaks as the FVS begins every year.During the FVS in 2020, 4 out of the 5 countries with the highest incidence of COVID-19 in children <15 years ranked in the top 5 studied countries with the highest increase in online search of flu vaccine.
European online search patterns of flu vaccination during the COVID-19 pandemic