NAbs against live wild-type SARS-CoV-2
subvariant
Participants in the low-dose and high-dose aerosolised Ad5-nCoV groups showed NAb GMTs against live wild-type SARS-CoV-2 of 1910.54 (95% CI 1391.98, 2622.28), 1635.03 (95% CI 1112.16, 2403.73) at day 28, 530.06 (95% CI 412.49, 681.12), 457.57 (95% CI 349.40, 599.22) at month 3, 312.88 (95% CI 237.71, 411.82), 251.12 (95% CI 178.16, 353.96) at month 6, and 204.36 (95% CI 152.91, 273.14), 171.38 (95% CI 121.27, 242.19) at month 12, which were significantly higher than those of the CoronaVac group, with GMT ratios of 25.97 and 22.42 folds at month 3, 29.94 and 24.04 folds at month 6, 25.58 and 21.41 folds at month 12, respectively (NAbs against live wild-type SARS-CoV-2 and omicron BA.1 subvariant after a booster vaccination. Horizontal bars show GMTs and error bars show 95% confidence intervals. Data (folds) above the bars are the NAb GMT ratios of the homologous boost group to the heterologous boost group. Long lines connecting the GMTs of adjacent groups indicate trends in NAbs over days after a booster vaccination. Data (%) above the bars show the percent reduction in GMTs of NAb titres at day 90, day 180 and day 360 post-boost compared to day 28. All horizontal dotted lines denote the cutoff levels for positivity (1:8) or the levels of WHO international standard (NIBSC code 20/136). Data below the cutoff level were assigned half the limit. GMT = geometric mean titre in serum. NAb = neutralizing antibody.The low-dose and high-dose aerosolised Ad5-nCoV groups had substantially higher GMFIs from the baseline Nab GMTs before the boosting than did the CoronaVac group at month 3 (139.58 [95% CI 100.75, 193.40] and 110.18 [95% CI 76.73, 158.23] vs. 5.56 [95% CI 3.63, 8.51]), month 6 (84.14 [95% CI 58.17, 121.70], 60.41 [95% CI 39.95, 91.33] vs. 2.80 [95% CI 1.96, 4.00]) and month 12 (47.67 [95% CI 33.44, 67.96], 39.83 [95% CI 26.33, 60.26] vs. 1.80 [95% CI 1.02, 3.16]) (Table S2). In addition, all participants (100%) in the low-dose and high-dose groups were serum seropositive for NAb GMTs against live wild-type SARS-CoV-2 at all pre-specified time points till month 12, while 85.00% (34/40), 66.67% (26/39) and 61.54% (8/13) of the participants in the CoronaVac group had seropositivity at month 3, month 6 and month 12, respectively (Table S2).