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In Vitro Neutralizing Activity of BNT162b2 mRNA-Induced Antibodies Against B.1.351 SARS-CoV-2 Variant in Pre-Exposed and Non-Pre-Exposed Vaccinees
18 Pages Posted: 7 May 2021
More...Abstract
Background: SARS-CoV-2 variation represents a serious challenge to current COVID-19 vaccines. Recent reports suggest that B.1.351 and P1/P2 variants may escape the neutralization activity of the antibodies generated by BNT162b2 mRNA vaccine.
Methods: Ninety-nine healthcare workers undertaking BNT162b2 mRNA vaccination were sampled at baseline, on the day of the second dose, and 14 days after the latter. Neutralization activity against SARS-CoV-2 B.1, B.1.1.7 and B.1.351 was investigated using a Vero-E6 model.
Results: Eleven of the study participants had prior infection with SARS-CoV-2. Neutralization titers against the B.1 and the B.1.1.7 variants were not statistically different and were significantly higher than titers against the B.1.351 variant across pre-exposed and non-pre-exposed vaccinated individuals (p<0.01). While all vaccinated individuals presented neutralizing antibodies against B.1 and B 1.1.7 after the second dose, 14% were negative against B.1.351, and 76% had low titers (1/20-1/80). Pre-exposed vaccinated individuals showed higher titers than non-pre-exposed after the first (median titers of 1/387 versus 1/28, respectively) and the second doses (1/995 versus 1/703, respectively). As high as 72% of the pre-exposed vaccinees presented titers >1/80 after a single dose, while only 11% of non-exposed vaccinated individuals had titers >1/80.
Conclusions: BNT162b2 mRNA-induced antibodies show a lower in vitro neutralizing activity against B.1.351 variant compared to neutralization against B.1.1.7 or B.1 variants. Interestingly, for individuals pre-exposed to SARS-CoV-2, one dose of BNT162b2 mRNA may be adequate to produce neutralizing antibodies against B.1.1.7 and B.1, while two doses of BNT162b2 mRNA provide optimal neutralizing antibody response against B.1.351 too.
Funding Statement: None to declare.
Declaration of Interests: None to declare.
Ethics Approval Statement: The protocol was approved by the Ethics Committee of the Hospital Universitario Clínico San Cecilio (HUSC 0670-N-21). All participants provided informed consent.
Keywords: SARS-CoV-2, neutralization, B.1, B.1.1.7, B.1.351, variants, BNT162b2 mRNA.
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