For the fifth day in a row, the data on infections in the United Kingdom indicate a reassuring decline. They always remain high, but the decline suggests a way out and, in this context, seems to agree with those who believe that the country has reached its peak. About Omicron? And what is really known about the new variant which, despite being very contagious, does not necessarily imply a surge in hospitalizations and deaths? In fact, the United Kingdom, the first European country to suffer the invasion of infections from Omicron, becomes a sort of litmus test for the rest of Europe, including Italy today struggling with a strong rise in Covid cases.