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.