Figure.

Neutralization of SARS-CoV-2 variants among vaccine-boosted persons with and without prior Omicron BA.1/BA.2 infections, Denmark. A) PRNT₉₀ titers against SARS-CoV-2 Delta variant and Omicron variants BA.1, BA.2, and BA.5. B) Correlation between the levels of spike antibodies and PRNT₉₀ titers. Participants received 3 doses of BNT162b2 (Pfizer-BioNTech, https://www.pfizer.com), 2 initial vaccines and a booster dose. We analyzed titers for 24 vaccinated participants (blue dots) who received 3 BNT162b2 doses only and 12 convalescent participants (red dots) who received 3 vaccine doses and had Omicron BA.1/BA.2 infection. For statistical analysis, a Kruskal-Wallis test was applied initially to account for the multiple comparisons problem. Subsequently, unpaired PRNT₉₀ titers were compared with the Wilcoxon rank-sum test, whereas paired PRNT₉₀ titers were compared with the Wilcoxon sign rank test. Red horizontal lines indicate neutralization threshold; horizontal bars indicate median neutralization titer for each SARS-CoV-2 strain. BAU, binding antibody units; C, convalescent participant; PRNT₉₀, plaque reduction neutralization tests with plaque reduction >90%; V, vaccinated participant.