Europe's healthcare systems are being strained once again by the rapid spread of the Omicron variant of the coronavirus over the holiday period, with large numbers of key staff ill or self-isolating and experts predicting the peak of infections is yet to come.

Despite early studies showing a lower risk of severe disease or hospitalisation from Omicron compared to the previously-dominant Delta variant, healthcare networks across Spain, Britain, Italy and beyond have found themselves in increasingly desperate circumstances...