Antibody titres decline 3-month post-vaccination with BNT162b2

Area of Science:

• Immunology
• Vaccinology
• Pharmacokinetics

Background:

• Limited data exists on antibody kinetics 3 months post-BNT162b2 mRNA COVID-19 vaccination, crucial for future vaccination strategies.
• The CRO-VAX HCP study investigates the humoral immune response in healthcare professionals after two BNT162b2 vaccine doses.

Purpose of the Study:

• To assess the antibody response kinetics following the BNT162b2 mRNA COVID-19 vaccine.
• To determine antibody half-life and time to maximum concentration in seronegative and seropositive individuals.

Main Methods:

• Prospective, interventional study involving 200 healthcare professionals.
• Antibody levels against SARS-CoV-2 nucleocapsid and spike protein receptor-binding domain measured at baseline and up to 90 days post-first dose.
• One-compartment kinetics model applied to estimate antibody half-life and time to maximum concentration.

Main Results:

• Antibody levels peaked around 24-36 days post-first dose, with higher levels in initially seropositive individuals.
• Estimated antibody half-life was 55 days in seronegative and 80 days in seropositive participants.
• A significant decline in antibody levels was observed at 90 days compared to peak response in all participants.

Conclusions:

• The BNT162b2 mRNA vaccine elicits a robust humoral response, though antibody levels decline by 3 months.
• Antibody kinetics differ between individuals who were seropositive or seronegative at baseline.
• Findings provide valuable insights for optimizing COVID-19 vaccination strategies.