‘Get boosted now’ is the government’s new slogan. In tonight’s address to the nation, Boris Johnson announced that he was bringing forward his timeline of offering a booster jab to all eligible adults by one month: from the end of January to New Year’s Eve. The heavy push for third doses is the government’s latest attempt to curb the spread of the Omicron variant, which early evidence suggests is more likely to transmit amongst double-vaccinated people (though there is still no evidence, either way, that the variant undercuts vaccine efficacy for protecting against severe illness).