Longitudinal analysis of antibody responses by vaccine brand and route, including Omicron BA.1 neutralization
We tracked these antibody and T cell responses longitudinally from pre-vaccine baseline to post-dose 3 by vaccine brand in Fig. 4 and 5. Very few (6 out of 30, 20%) participants seroconverted after a single dose of vaccine. Two doses of both vaccines significantly induced WT S-RBD IgG (both P<0.01) and WT sVNT (both P<0.01) (Fig. 4A-B). Bloods were additionally drawn at pre-dose 3 for patients who received dose 3 at least 70 days (mean 150 days) after dose 2, and significant decline of sVNT levels was observed after BNT162b2 only (P=0.022). WT S-RBD IgG levels were also significantly increased by a third dose of BNT162b2 (P=0.037) and increasing trends of WT S-RBD for CoronaVac and WT sVNT for both vaccines were also observed post-dose 3 compared to post-dose 2. Neutralization responses in those who received an intradermal third dose appeared high (all four >85% inhibition), and all were higher than the respective GM by vaccine brand and dose.
Neutralization capacity of patient sera against Omicron BA.1 was evaluated by sVNT which found most patients who received 2 doses of vaccine (89% for BNT162b2 and 100% for CoronaVac) could not neutralize BA.1 (Fig. 4C), indicating that BA.1 markedly evades neutralization in IEI patients. BA.1 sVNT levels were significantly increased by dose 3 of BNT162b2 (P=0.043) but not CoronaVac, although dose 3 CoronaVac did elicit BA.1 neutralization response in 1 out of 6 patients tested.