Vaccine-Induced Antibody Responses against SARS-CoV-2 Variants-Of-Concern Six Months after the BNT162b2 COVID-19 mRNA Vaccination

Abstract

A decrease in vaccine efficacy against emerging SARS-CoV-2 variants has increased the importance of assessing the persistence of SARS-CoV-2 spike protein-specific antibodies and neutralizing antibodies. Our data show that after 6 months post two doses of BNT162b2 vaccine, antibody levels decrease yet remain detectable and capable of neutralizing emerging variants. By monitoring the vaccine-induced antibody responses, vaccination strategies and administration of booster doses can be optimized.

Comparative analysis of COVID-19 vaccine responses and third booster dose-induced neutralizing antibodies against Delta and Omicron variants

“…BNT162b2 vaccine-induced antibody responses with a short vaccine dose interval and the effect of a third booster dose. HCWs receiving 2x BNT162b2 vaccine with a short 3-week vaccine dose interval have been analyzed in our previous studies for the antibody levels at 6 weeks 14 (n = 180) and 6 months 7 (n = 52) after the second dose. Here we analyzed the antibody levels of 120 HCWs randomly selected from the above-mentioned cohort and extended the follow up to 9 months after the second vaccine dose.…”

“…Microneutralization test. The neutralization capacity of the serum samples was measured by microneutralization test (MNT) as described previously 7 . Briefly, two-fold dilution series starting from 1:10 dilution was prepared on 96-well plate for each serum into 50 µl of DMEM supplemented with 2% fetal bovine serum (FBS), 2 mM L-glutamine, and penicillin-streptomycin.…”

“…However, the antibody levels decline, and the surveillance of vaccine effectiveness and the decline of immune responses highlighted the need for a vaccine booster dose in the first group of vaccinees who received the vaccines within a 3-week interval 7,8 . Initial studies have shown that a third dose of COVID-19 vaccines strongly boost the waning immune responses and on the population level reduced severe COVID-19-associated morbidity and mortality [9][10][11] .…”

Persistent T cell-mediated immune responses against Omicron variants after the third COVID-19 mRNA vaccine dose

“…Participants (n = 100) were selected randomly, and they were 25-65 years old (mean 43 years, standard deviation (SD) 11 years) and 91% were female. SARS-CoV-2-speci c IgG antibody levels were measured with enzyme immunoassay (EIA) and as shown previously 10,11 , the second vaccine dose induced a high levels of spike protein subunit 1 (S1) speci c antibodies, which declined in the subsequent months. The third vaccine dose effectively restored the amount of spike protein-speci c antibodies, and the levels were even higher compared with the levels seen after the second dose (p < 0.0001) (Fig.…”

“…The vaccinees with steadily elevated anti-N IgG antibodies and with no known previous SARS-CoV-2 infection (n = 3, Fig. 1c) are likely due to crossreactive antibodies from previous seasonal coronavirus infections 11 .…”