Figure 5.

Live virus neutralisation titres against delta and omicron variant strains, before and 28 days after boost vaccination by booster vaccine groups

In each group, ten samples were selected from each age group (18–60 years, 61 years and older). Lines connect values from the same participant. Dotted line shows lower limit of the assay. Values below the limit were substituted with a titre of 10. Participants with antibody titres above the lower limit are considered seropositive and are shown as percentages. The midlines of the boxes show medians and the outer bounds of the boxes show IQRs. Error bars extend to the last data point within 1·5 × the IQR above or below the 75th or 25th percentile. See appendix (p 14) for summary statistics. Ad26=Ad.26.COV2-S (n=20). BNT=BNT162b2 (n=20). ChAd=ChAdOx1 nCoV-19 (n=20). CV=CoronaVac (n=20). FRNT₅₀=Focus reduction neutralisation test—the reciprocal dilution of serum that neutralises 50% of the input virus (appendix p 11).