Figure 5.

Neutralising antibody response measured by plaque reduction neutralisation test (PRNT). Geometric mean neutralising antibody titres were compared from baseline (day 0) to day 42 (14 days after the second dose). The serum neutralisation titres were defined as the median neutralising titre (ND₅₀). The titres of neutralisation assay were converted to international unit (IU)/mL using WHO international standard (NIBSC 20/136). GMT, Geometric mean titre; SD, standard deviation; SCR, seroconversion rate.