… The purpose of this study was to evaluate whether a bivalent COVID-19 vaccine protects against COVID-19

… Employees of Cleveland Clinic in employment on the day the bivalent COVID-19 vaccine first became available

… Among 51011 employees … 42064 (83%) had received at least two doses of a COVID-19 vaccine

… The risk of COVID-19 also varied by the number of COVID-19 vaccine doses previously received

… The higher the number of vaccines previously received, the higher the risk of contracting COVID-19

… the current bivalent vaccines were about 30% effective overall in protecting against infection with SARS-CoV-2

… The association of increased risk of COVID-19 with higher numbers of prior vaccine doses in our study, was unexpected

… This is not the only study to find a possible association with more prior vaccine doses and higher risk of COVID-19

… is important to examine whether multiple vaccine doses given over time may not be having the beneficial effect that is generally assumed