Early Onset of SARS-COV-2 Antibodies after First Dose of BNT162b2: Correlation with Age, Gender and BMI

Pellini, Raul; Venuti, Aldo; Pimpinelli, Fulvia; Abril, Elva; Blandino, Giovanni; Campo, Flaminia; Conti, Laura; De Virgilio, Armando; De Marco, Federico; Di Domenico, Enea Gino; Di Bella, Ornella; Di Martino, Simona; Ensoli, Fabrizio; Giannarelli, Diana; Mandoj, Chiara; Manciocco, Valentina; Marchesi, Paolo; Mazzola, Francesco; Moretto, Silvia; Petruzzi, Gerardo; Petrone, Fabrizio; Pichi, Barbara; Pontone, Martina; Zocchi, Jacopo; Vidiri, Antonello; Vujovic, Branka; Piaggio, Giulia; Morrone, Aldo; Ciliberto, Gennaro

Background: The first goal of the study was to analyse the antibody titre 21 days after the first dose of the BNT162b2 vaccine in a group of 252 healthcare workers (HCW). The second goal was to analyse how the antibody titre changes in correlation with age, gender and body mass index (BMI). Methods: Participants had a nasopharyngeal swab for SARS-CoV-2 and were assessed for the presence of SARS-CoV-2 antibodies at baseline and 21 days after the BNT162b2 priming dose. Results: First dose of BNT162b2 activated immune responses in 98% of the participants. Five HWC had no increase in antibody titre 21 days after the first dose. Antibody titre was greater in young (<38 years) vs. older participants (<38 vs. 47–56 p = 0.002; <38 vs. >56 p = 0.001). Higher antibody levels were detected in underweight vs. pre-obesity group (p = 0.026) and in normal-weight vs. pre-obesity group (p = 0.007). This association was confirmed after adjusting for age (p = 0.0001) and gender (p = 0.00001). Conclusions: Our study demonstrates that a single dose of BNT162b2 activates the immune response, and being young and normal-weight correlate positively with this response. Larger specifically designed clinical trials are needed to validate these results.