The Influence of Two Priming Doses of Different Anti-COVID-19 Vaccines on the Production of Anti-SARS-CoV-2 Antibodies after the Administration of the Pfizer/BioNTech Booster

Introduction: A global vaccination program was implemented in late 2020 to end the pandemic caused by the SARS-CoV-2 virus. However, the immune response elicited by the vaccines proved to be insufficient due to the rapid emergence of new viral mutations. Therefore, the factors influencing cellular and humoral immune responses after the administration of different vaccines against SARS-CoV2 need to be identified.Materials: In the present study, anti-SARS-CoV-2 antibody titers were analyzed 20 to 50 days after the administration of a third (booster) dose of the BNT162b2 vaccine in 192 residents of the city of Olsztyn (Poland) primed with two AstraZeneca or Pfizer/ BioNTech vaccines. Methods: Antibody titers were determined in venous blood serum in the ECLIA test using the Cobas e411 Roche analyzer.Results: The study revealed that persons who received three doses of the Pfizer/BioNTech vaccine had significantly higher antibody titers than those who received two doses of AstraZeneca and a booster dose of Pfizer/BioNTech.Keywords: vaccination, COVID-19, BNT162b2, ChAdOx1, anti-SARS-CoV-2