The COVID-19 pandemic still goes on. The increasing number of COVID-19 cases has been observed since the start of summer 2022, although this was not in summer 2021. Therefore, we would like to compare factors that were responsible for this trend in five selected countries in the European Union (Greece, Italy, Slovenia, Austria and Germany) using the data from publicly available databases for the analyzed period of weeks 22-30 in 2021 and 2022. The multiple factor analysis was conducted in R, using mean or median score. Our cross-sectional study showed that analyzed countries had similar profiles in 2021 characterized by restrictions and health system policies, as well as B.1.351, B.1.1.7, B.1.617.2 and P.1 variants. Similarly, these countries had similar profiles in 2022, but described by other variables: number of new COVID-19 cases per million, number people fully vaccinated per hundred, number of total boosters administered per hundred and also occurrence of Omicron variant and its sub-lineages. Although the COVID-19 vaccination rate is relatively high in the European Union, during the summer of 2022, the number of COVID-19 cases sharply increased daily, which seems to be connected with the presence of the Omicron variant and its sub-lineages.
Keywords: COVID-19; Omicron; SARS-CoV-2; multiple factor analysis; restrictions; vaccination.