Cross-neutralization of SARS-CoV-2 B.1.1.7 and P.1 variants in vaccinated, convalescent and P.1 infected

Gidari, Anna; Sabbatini, Samuele; Bastianelli, Sabrina; Pierucci, Sara; Busti, Chiara; Monari, Claudia; Pasqua, Barbara Luciani; Dragoni, Filippo; Schiaroli, Elisabetta; Zazzi, Maurizio; Francisci, Daniela

OBJECTIVES: : The emergence of new variants of concern (VOCs) of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) around the world significantly complicated the exit from Coronavirus disease 2019 (COVID-19) pandemic. The aim of this study was to evaluate the serum neutralizing activity of three cohorts. METHODS: : BNT162b2-elicited serum (N=103), candidates as hyper-immune plasma donors (N=90) and patients infected with the SARS-CoV-2 P.1 variant (N=22) were enrolled. Three strains of SARS-CoV-2 have been tested: 20A.EU1, B.1.1.7 (alpha) and P.1 (gamma). Neutralizing antibodies (NT-Abs) titers against SARS-CoV-2 were evaluated. RESULTS: : B.1.1.7 and P.1 are less efficiently neutralized by convalescent wild-type infected serums if compared to 20A.EU1 strain (mean titer 1.6 and 6.7-fold lower respectively). BNT162b2 vaccine-elicited human sera show an equivalent neutralization potency on the B.1.1.7 but it is significantly lower for the P.1 variant (mean titer 3.3-fold lower). Convalescent P.1 patients are less protected from other SARS-CoV-2 strains with an important reduction of neutralizing antibodies against 20A.EU1 and B.1.1.7, about 12.2 and 10.9-fold, respectively. CONCLUSIONS: : BNT162b2 vaccine confers immunity against all the tested VOCs, while previous SARS-CoV-2 infection may be less protective.