Serum neutralisation titres following fifth dose vaccination in eligible participants compared between fifth dose vaccine received. In all panels, p values were determined using unpaired two-tailed Wilcoxon signed-rank tests, and where calculated, the median fold-change between titres from before and after vaccination and the 95% CI are provided (details of methods are provided in theappendix [pp 1011]). An analysis of paired data is shown in theappendix (p 3). FC=fold change. IC50=half-maximal inhibitory concentration. UCLH=University College London Hospital.