BNT162b2-Elicitated serum neutralizing activity

To the editor:

BNT162b2 is a nucleoside-modified RNA vaccine that expresses complete infusion of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) glycoprotein (S) glycoprotein. In a randomized, placebo-controlled clinical trial with nearly 44,000 participants, vaccination conferred 95% efficacy against coronavirus disease 2019 (COVID-19).1

New highly transmissible variants of SARS-CoV-2 were first detected in the UK (strain B.1.1.7), South Africa (strain B.1.351) and Brazil (strain P.1) with mutations in s The gene is spread worldwide. To analyze the effects on the equation induced by BNT162b2, we designed s Mutations from each of the three new strains in USA-WA1/2020, a relatively early isolation of the virus as of January 2020 (Figure S1 in the Supplementary Appendix, available with the full text of this letter at Thus, we generated three recombinant viruses representing each of these strains and two additional viruses in which we modeled subsets of mutations in the B.1.351 strain. Thus, the first recombinant virus had all the mutations in s The gene is in the B.1.1.7 lineage (B.1.1.7-spike), the second having all the mutations in s The gene is in the P.1 strain (P.1-spike), and the third has all the mutations found in s The gene in the B.1.351 strain (B.1.351-spike), the fourth had an N-terminal domain deletion present in the B.1.351 strain and the globally dominant D614G substitution (B.1.351-∆242-244 + D614G), and the fifth had the three mutations of the strain B.1.351 affecting amino acids at the receptor binding site (K417N, E484K, and N501Y) and the D614G substitution (B.1.351-RBD + D614G). The mutant amino acid residues in the recombinant B.1.351-RBD+D614G virus are also among those in the P.1 lineage virus, although in the P.1 lineage virus K417 is mutated to threonine rather than asparagine. All mutant viruses yielded an infective viral titer greater than 10 .7 Plaque forming units per milliliter. The B.1.1.7-spike and B.1.351-spike viruses formed smaller plaques than those formed by other viruses (Fig. S2).

Serum neutralization of altered strains of SARS-CoV-2 after the second dose of BNT162b2 vaccine.

The results of the 50% Plaque Reduction Neutralization Test (PRNT .) are shown50) using 20 samples obtained from 15 trial participants for 2 weeks (rings) or 4 weeks (triangles) after the second dose of BNT162b2 vaccine was administered. The mutant viruses were obtained by engineering a full set of mutants in the B.1.1.7 or P.1 lineages. or B.1.351 or subsets of s Gene mutations in the B.1.351 lineage (B.1.351-Δ242-244 + D614G and B.1.351-RBD + D614G) in USA-WA1 / 2020. Each data point represents the geometric mean PRNT50 Obtained with a serum sample against the indicated virus, including data from repeated experiments, as detailed in Table S1 in the Supplementary Appendix. USA-WA1/2020 data are from three trials; For viruses B.1.1.7-spike, B.1.351-Δ242-244 + D614G, and B.1.351-RBD-D614G from one experiment each; and for the P.1-spike and B.1.351-spike viruses from two trials each. In each experiment, the neutralization titer was determined in duplicate assays, and the geometric mean was taken. The heights of the bars and the numbers above the bars indicate mean geometric titers. Bars indicate 95% confidence intervals. Statistical analysis was performed using the Wilcoxon site classification test. The statistical significance of the difference between the geometric mean titers in the USA-WA1/2020 neutralization assay and in each virus neutralization variable assay with the same serum samples is as follows: P = 0.02 for B.1.1.7-spike; P = 0.06 for P.1-spike; P < 0.001 for B.1.351-spike; P = 0.99 for B.1.351-Δ242-244 + D614G; and P = 0.005 for B.1.351-RBD + D614G. LOD indicates the detection limit.

We performed a 50% plaque reduction neutralization test (PRNT .).50) using 20 serum samples obtained from 15 participants in the pivotal trial1,2 2 or 4 weeks after administration of a second dose of 30 mcg of BNT162b2 (which occurred 3 weeks after the first immunization) (Fig. S3). All serum samples were efficiently neutralized by USA-WA1/2020 and all mutant spike spikes. Almost all of them did so with a benchmark above 1:40. Mean geometric titer equivalent vs. USA-WA1/2020, B.1.1.7-spike, P.1-spike, B.1.351-spike, B.1.351-∆242-244 + D614G, and B.1.351-RBD + D614G viruses were 532, 663, 437, 194, 485, and 331, respectively (shape 1 and Table S1). Thus, compared with the USA-WA1/2020 neutralization, the neutralization of B.1.1.7-spike and P.1-spike viruses was approximately equivalent, and the neutralization of B.1.351-spike virus was strong but less. Our data are also consistent with lower neutralization titers against the virus with the full set of B.1.351-spike mutations compared to the virus with any subgroup of mutations. Our findings also suggest that mutations leading to the K417N, E484K and N501Y amino acid substitutions at the receptor binding site have a greater effect on neutralization than the 242–244 deletion affecting the N-terminal domain of the spike protein.

Limitations of the study include the potential for mutations to change the equation by affecting spike function rather than antigenicity. Therefore, each neutralization assay with a different target virus is unique, and comparisons of neutralization titres from different assays should be interpreted with caution. Neutralizing activity against B.1.351 lineage virus was robust at a geometric mean significantly higher than that obtained after a single dose of BNT162b2, when strong efficacy was already observed in the C4591001 efficacy trial.1-3 T-cell immunity may also be involved in protection,4 BNT162b2 immunization elicits CD8+ T cell responses that recognize multiple variants.5 Ultimately, conclusions about vaccine-mediated protection that are extrapolated from the equation or T-cell data must be validated by real-world evidence collected in regions where SARS-CoV-2 variants are circulating.

Yang Liu, Ph.D.
Jianying Liu, Ph.D.
Hongjie Chia, Ph.D.
Xianwen Zhang, B.S.
Camilla R. Fontes-Garvias, Ph.D.
University of Texas Medical Branch, Galveston, Texas

Enter A. Swanson, Ph.D.
Hoi Kai, Ph.D.
Ritu Sarkar, MA
Wei Chen, MS
Mark Cutler, Ph.D.
David Cooper, Ph.D.
Pfizer Vaccine Research and Development, Pearl River, New York

Scott C. Weaver, Ph.D.
University of Texas Medical Branch, Galveston, Texas

Alexander Moek, Ph.D.
Ugur Sahin, MD
BioNTech, Mainz, Germany

Katherine Yu Janssen, Ph.D.
Pfizer Vaccine Research and Development, Pearl River, New York

Xuping Xie, Ph.D.
University of Texas Medical Branch, Galveston, Texas
[email protected]

Philip R. Dormitser, MD, PhD.
Pfizer Vaccine Research and Development, Pearl River, New York
[email protected]

Bi Yong-shi, Ph.D.
University of Texas Medical Branch, Galveston, Texas
[email protected]

Powered by Pfizer and BioNTech.

Disclosure forms provided by the authors are available with the full text of this letter at

An initial version of this letter was published on February 17, 2021, and updated on March 8, 2021, at

Dr.. Y. Liu and J. Liu contributed equally to this letter.

  1. 1. Polack FPAnd Thomas SJAnd Kitchen n, and others. Safety and efficacy of the BNT162b2 mRNA Covid-19 vaccine. In Angel J Med 2020; 383:26032615.

  2. 2. Walsh EAnd Frink RW Jr.And Error, and others. Safety and immunogenicity of two RNA-based Covid-19 vaccines. In Angel J Med 2020; 383:24392450.

  3. 3. Shaheen YuAnd MuikAnd Vogler i, and others. BNT162b2 induces neutralization of SARS-CoV-2 antibodies and T cells in humans. December 11And 2020 ( pre-print.

  4. 4. Liao MAnd Liu WeiAnd yuan c, and others. Single-cell landscape of bronchoalveolar immune cells in COVID-19 patients. nat med 2020; 26:842844.

  5. 5. Skelli DTAnd Harding ACAnd Gilbert-Jaramillo J, and others. Vaccine-induced immunity provides heterogeneous immunity that is stronger than natural infection of the emerging SARS-CoV-2 variants of concern. February 9And 2021 ( pre-print.

Leave a Reply

Your email address will not be published.