As England moves to plan B, Boris Johnson has announced that all adults will be offered a booster vaccine by the end of December. But will that be enough to protect the NHS from being overwhelmed? Madeleine Finlay speaks to the Guardian’s science editor, Ian Sample, about the spread of Omicron, and what we can do to prevent a tidal wave of cases. Help support our independent journalism at theguardian.com/sciencepod