Confounding factors influencing the kinetics and magnitude of serological response following administration of BNT162b2

Jean-Louis Bayart, Laure Morimont, Mélanie Closset, Grégoire Wieërs, Tatiana Roy, Vincent Gerin, Marc Elsen, Christine Eucher, Sandrine Van Eeckhoudt, Nathalie Ausselet, Clara David, François Mullier, Jean-Michel Dogné, Julien Favresse, Jonathan Douxfils

Research output: Contribution to journalArticlepeer-review


BACKGROUND: Little is known about potential confounding factors influencing the humoral response in individuals having received the BNT162b2 vaccine.

METHODS: Blood samples from 231 subjects were collected before and 14, 28, and 42 days following coronavirus disease 2019 (COVID-19) vaccination with BNT162b2. Anti-spike receptor-binding-domain protein (anti-Spike/RBD) immunoglobulin G (IgG) antibodies were measured at each time-point. Impact of age, sex, childbearing age status, hormonal therapy, blood group, body mass index and past-history of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection were assessed by multivariable analyses.

RESULTS AND CONCLUSIONS: In naïve subjects, the level of anti-Spike/RBD antibodies gradually increased following administration of the first dose to reach the maximal response at day 28 and then plateauing at day 42. In vaccinated subjects with previous SARS-CoV-2 infection, the plateau was reached sooner (i.e., at day 14). In the naïve population, age had a significant negative impact on anti-Spike/RBD titers at days 14 and 28 while lower levels were observed for males at day 42, when corrected for other confounding factors. Body mass index (BMI) as well as B and AB blood groups had a significant impact in various subgroups on the early response at day 14 but no longer after. No significant confounding factors were highlighted in the previously infected group.

Original languageEnglish
Article number1340
Issue number6
Publication statusPublished - 21 Jun 2021


  • Age
  • Antibody
  • Blood-group
  • BMI
  • BNT162b2
  • Gender
  • Kinetic
  • SARS-CoV-2
  • Serology
  • Vaccine


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