Cross-neutralization of Omicron subvariants after heterologous NVX-CoV2373 boosters: Comparison between prior SARS-CoV-2-infected and infection-naive individuals

•We investigated the cross-reactive immunity against omicron BA.1/BA.5 in the individuals with heterologous NVX-CoV2373 booster.•Both third- and fourth-dose heterologous NVX-CoV2373 boosters enhanced cross-reactive immunity against omicron BA.1/BA.5 subvariants.•Remarkable ceiling effects were observed in the individuals with prior SARS-CoV-2 infection.•Prior SARS-CoV-2 infection may provide better cross-protection against diverse omicron subvariants.