Fig. 3: Third vaccine dose enhances neutralization of Delta and Omicron BA.1 and BA.5.

a, Antibody neutralization of Delta variant after third vaccine in relation to prior natural infection and age. Red dots indicate participants with prior natural infection and black dots indicate non-infected donors. Kruskal–Wallis (uncorrected Dunn’s test), *P = 0.015, **P = 0.003, ****P = 0.0001, n = 195. Black line indicates the median. No prior infection <65 versus >65 years old, Chi-squared test: Fisher’s exact, P = 1.000. Top and bottom dotted lines indicate the continuous region of the data obtained. Between middle and bottom regions is the weak inhibition region. b, Antibody neutralization of Omicron variant BA.1 after third vaccine in relation to prior natural infection and age. Red dots indicate participants with prior natural infection and black dots indicate non-infected donors. Kruskal–Wallis (uncorrected Dunn’s test), *P = 0.03, **P = 0.003, ****P = 0.0001, n = 195. Black line indicates the median. No prior infection <65 versus >65 years old, Chi-squared test: Fisher’s exact, P = 0.596. Top and bottom dotted lines indicate the continuous region of the data obtained. Between middle and bottom regions is the weak inhibition region. c, Antibody neutralization of Omicron variant BA.5 after third vaccine in relation to prior natural infection and age. Red dots indicate participants with prior natural infection and black dots indicate non-infected donors. Kruskal–Wallis (uncorrected Dunn’s test) *P = 0.01, **P = 0.004, n = 195. Black line indicates the median. No prior infection <65 versus >65 years old, Chi-squared test: Fisher’s exact, P = 0.46. Top and bottom dotted lines indicate the continuous region of the data obtained. Between middle and bottom regions is the weak inhibition region.