BNT162b2 SARS-CoV-2 Vaccination Elicits High Titers of Neutralizing Antibodies to Both B.1 and P.1 Variants in Previously Infected and Uninfected Subjects

• Main Authors: Ilaria Vicenti, Francesca Gatti, Renzo Scaggiante, Adele Boccuto, Daniela Zago, Monica Basso, Filippo Dragoni, Saverio Giuseppe Parisi, Maurizio Zazzi
• Format: Article
• Language: English
• Published: MDPI AG 2021-08-01
• Series: Life
• Subjects: SARS-CoV-2 vaccination; neutralizing antibodies; live virus neutralization; B.1 variant; P.1 variant; previously infected and uninfected subjects
• Online Access: https://www.mdpi.com/2075-1729/11/9/896

We aimed to investigate neutralizing antibody titers (NtAbT) to the P.1 and B.1 SARS-CoV-2 variants in a cohort of healthy health care workers (HCW), including 20 previously infected individuals tested at baseline (BL_inf, after a median of 298 days from diagnosis) and 21 days after receiving one vaccine dose (D1_inf) and 15 uninfected subjects tested 21 days after the second-dose vaccination (D2_uninf). All the subjects received BNT162b2 vaccination. D1_inf NtAbT increased significantly with respect to BL_inf against both B.1 and P.1 variants, with a fold-change significantly higher for P.1. D1_inf NtAbT were significantly higher than D2_uninf NtAbT, against B.1 and P.1. NtAbT against the two strains were highly correlated. P.1 NtAbT were significantly higher than B.1 NtAbT. This difference was significant for post-vaccination sera in infected and uninfected subjects. A single-dose BNT162b2 vaccination substantially boosted the NtAb response to both variants in the previously infected subjects. NtAb titers to B.1 and P.1 lineages were highly correlated, suggesting substantial cross-neutralization. Higher titers to the P.1 than to the B.1 strain were driven by the post-vaccination titers, highlighting that cross-neutralization can be enhanced by vaccination.