Neutralizing antibody titers were determined against lentivirus pseudotyped with S from the BA.4/5-derived (A, B and C) or BA.2.75 (D, E, and F) mutants for sera from health care workers (HCWs) (A and D) (n = 15) who received a single homologous monovalent Moderna mRNA-1273 (n = 3) or Pfizer/BioNTech BNT162b2 (n = 12) mRNA booster vaccination; for sera from BA.1-wave hospitalized COVID-19 patients (B and E) (n = 15); or for sera from BA.4/5-wave SARS-CoV-2 infected Columbus, Ohio first responders and household contacts (C and F) (n = 20). Bars represent geometric means with 95% confidence intervals. Geometric means are displayed at the top of the plots. Significance relative to parental variants was determined by one-way repeated measures ANOVA with Bonferroni’s multiple testing correction. P values are displayed as ns for p ≥ 0.05, *p < 0.05, **p < 0.01, and ****p < 0.0001.