Fig. 6From: Neutralising reactivity against SARS-CoV-2 Delta and Omicron variants by vaccination and infection historyNeutralisation titres against the B.1, B.1.617.2 and BA.1 SARS-CoV-2 variants in naïve and previously infected subjects according to vaccination. a Neutralising antibody titres against B.1, B.1.617.2 and BA.1 SARS-CoV-2 variants in (left) previously infected (Friedman test followed by Dunn’s multiple comparisons test, serum of previously infected subjects with one vaccine dose against B.1 versus B.1.617.2 and BA.1, P = 0.004 and P < 0.0001 respectively; serum of previously infected subjects with two vaccine doses against B.1 versus B.1.617.2 and BA.1, P = 0.02 and P < 0.0001, respectively) and (right) naïve subjects (Friedman test followed by Dunn’s multiple comparisons test, serum of naïve subjects with two doses of vaccine against B.1 versus B.1.617.2 and BA.1, P = 0.03 and P <0.0001, respectively). Asterisks indicate *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. b, c Fold changes in serum neutralisation titres of previously infected subjects with b one dose of vaccine and c two doses of vaccine tested for B.1.617.2 and BA.1 variants compared to B.1 (fold change of 4× and 16× for both one or two doses of vaccine for B.1.617.2 and BA.1, respectively). Previous infection is defined according to the ground truth definition given in the textBack to article page