While it never went away Covid-19 is back with a vengeance Hospitalisations of people with Covid-19 and case numbers are soaring, pushing our health system --already struggling with other winter illnesses -- to the brink.

The culprits are the new BA.4 and particularly BA.5 subvariants of Oh-micron. Immunologist Professor Graham Le Gros talks to us about how the variants are affecting us differently.