1. Neutralizing Immunity Induced Against the Omicron BA.1 and BA.2 Variants in Vaccine Breakthrough Infections
- Author
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Brazer, Noah, Morris, Mary Kate, Servellita, Venice, Anglin, Khamal, Saldhi, Prachi, Garcia-Knight, Miguel, Bethancourt, Sutana, Sotomayor-Gonzalez, Alicia, Wang, Baolin, Foresythe, Abiodun, Nguyen, Jenny, Gliwa, Amelia S, Pineda-Ramirez, Jesus, Sanchez, Ruth Diaz, Zhang, Yueyuan, Ott, Melanie, Wadford, Debra A, Andino, Raul, Kelly, J Daniel, Hanson, Carl, and Chiu, Charles Y
- Subjects
Medical Microbiology ,Biomedical and Clinical Sciences ,Immunology ,Emerging Infectious Diseases ,Prevention ,Vaccine Related ,Immunization ,Infectious Diseases ,Infection ,Good Health and Well Being ,Humans ,Antibodies ,Neutralizing ,Vaccines ,Antibodies ,Viral ,Omicron BA ,1 ,2 ,and Delta SARS-CoV-2 variants ,COVID-19 ,breakthrough infection ,neutralizing antibodies ,vaccine boosting ,Omicron BA.1 ,Omicron BA.2 ,Biological Sciences ,Medical and Health Sciences ,Microbiology ,Biological sciences ,Biomedical and clinical sciences ,Health sciences - Abstract
BackgroundAs of early 2022, the Omicron variants are the predominant circulating lineages globally. Understanding neutralizing antibody responses against Omicron BA.1 and BA.2 after vaccine breakthrough infections will provide insights into BA.2 infectivity and susceptibility to subsequent reinfection.MethodsLive virus neutralization assays were used to study immunity against Delta and Omicron BA.1 and BA.2 variants in samples from 86 individuals, 24 unvaccinated (27.9%) and 62 vaccinated (72.1%), who were infected with Delta (n = 42, 48.8%) or BA.1 (n = 44, 51.2%). Among the 62 vaccinated individuals, 39 were unboosted (62.9%), whereas 23 were boosted (37.1%).ResultsIn unvaccinated infections, neutralizing antibodies (nAbs) against the three variants were weak or undetectable, except against Delta for Delta-infected individuals. Both Delta and BA.1 breakthrough infections resulted in strong nAb responses against ancestral wild-type and Delta lineages, but moderate nAb responses against BA.1 and BA.2, with similar titers between unboosted and boosted individuals. Antibody titers against BA.2 were generally higher than those against BA.1 in breakthrough infections.ConclusionsThese results underscore the decreased immunogenicity of BA.1 compared to BA.2, insufficient neutralizing immunity against BA.2 in unvaccinated individuals, and moderate to strong neutralizing immunity induced against BA.2 in Delta and BA.1 breakthrough infections.
- Published
- 2022