Three mutant variants of the coronavirus that emerged in Britain, South Africa and Brazil pose a high risk in Europe and will lead to more COVID-19 infections, hospitalizations and deaths, Europe's disease surveillance agency said on Thursday.The variants, which contain mutations or changes to parts of the COVID-19-causing coronavirus that scientists say make them more transmissible, have already been detected in many countries in Europe and will likely continue to do so, the European Centre for Disease Prevention and Control (ECDC) said in a risk assessment."We are currently seeing deteriorating epidemiological situations in areas where more transmissible variants of the SARS-CoV-2 virus have become established," the ECDC's director Andrea Ammon said in a statement. "An increasing number of infections will lead to higher hospitalization and death rates across all age-groups."The risk assessment said European Union member states "should prepare their healthcare systems for a further escalation in demand."Britain and some EU countries have already closed or are considering closing borders to others to try and limit the spread of the more transmissible variants. But the European Commission has said such closures would harm the EU's single market.The ECDC advised against all but essential travel, and urged European governments to accelerate the pace of COVID-19 vaccinations for high-risk groups such as the elderly and healthcare workers. Ammon added that a combination of physical distancing, increased surveillance, sequencing of samples, rigorous contact tracing and quarantine were also needed to effectively curb the spread of the new variants.