CFB and infection: “Homotypic” antibodies (e.g., BA.1- or BA.2-neutralizing antibodies against BA.1 or BA.2 infections, respectively) significantly mediated protection, with mediation effect estimates indicating that every four-fold increase in titer mediated 11% (CI 4–21%, p = 0.006) and 12% (CI 6–24%, p = 0.002) protection from prior infection for infection and symptomatic infection, respectively (Fig. 2, Table S11).