Three-month ad interim analysis of total anti-SARS-CoV-2 antibodies in healthy recipient of a single BNT162b2 vaccine booster

The current cohort comprises 240 SARS-CoV-2 baseline seronegative subjects (median age 48 years, range 23–72 years; 151 females), who underwent primary COVID-19 vaccination with Comirnaty (two 30 µg doses, at 3-week interval), and subsequent administration of single homologous booster dose (30 µg) more than 8 months afterwards. A decline in the serum levels of total anti-SARS-CoV-2 antibodies could be observed from 1 to 3 months after receiving the BNT162b2 single booster dose. More specifically, the median serum values of total anti-SARS-CoV-2 antibodies significantly decreased from 22,094 kBAU at 1 month post-booster to 11,612 kBAU (mean decrease: 35±27%) at 3 months postbooster. The amplitude of such reduction was found to be more accentuated in people having lower 1-month post-booster values and younger age. All subjects included in this study still had considerably high values 3 month after the single vaccine booster.