Immunogenicity of convalescent and vaccinated sera against clinical isolates of ancestral SARS-CoV-2, Beta, Delta, and Omicron variants.

SARS-CoV-2 Omicron variant of concern (VOC) has evolved multiple mutations within the spike protein, raising concerns of increased antibody evasion. In this study, we assessed the neutralization potential of COVID-19 convalescent sera and sera from vaccinated individuals against ancestral SARS-CoV-2 and VOCs. The neutralizing activity of sera from 65 coronavirus disease (COVID-19) vaccine recipients and convalescent individuals against clinical isolates of ancestral SARS-CoV-2 and Beta, Delta, and Omicron VOCs was assessed using a micro-neutralization assay. Convalescent sera from unvaccinated individuals infected by the ancestral virus demonstrated reduced neutralization against Beta and Omicron VOCs. Sera from individuals that received three doses of the Pfizer or Moderna vaccines demonstrated reduced neutralization of the Omicron variant relative to ancestral SARS-CoV-2. Sera from individuals that were naturally infected with ancestral SARS-CoV-2 and subsequently received two doses of the Pfizer vaccine induced significantly higher neutralizing antibody levels against ancestral virus and all VOCs. Infection alone, either with ancestral SARS-CoV-2 or the Delta variant, was not sufficient to induce high neutralizing antibody titers against Omicron. In summary, we demonstrate that convalescent and vaccinated sera display varying levels of SARS-CoV-2 VOC neutralization. Data from this study will inform booster vaccination strategies against SARS-CoV-2 VOCs. This research was funded by the Canadian Institutes of Health Research (CIHR). VIDO receives operational funding from the Government of Saskatchewan through Innovation Saskatchewan and the Ministry of Agriculture and from the Canada Foundation for Innovation through the Major Science Initiatives for its CL3 facility.

Banerjee A ，Lew J ，Kroeker A ，Baid K ，Aftanas P ，Nirmalarajah K ，Maguire F ，Kozak R ，McDonald R ，Lang A ，Gerdts V ，Straus SE ，Gilbert L ，Li AX ，Mozafarihashjin M ，Walmsley S ，Gingras AC ，Wrana JL ，Mazzulli T ，Colwill K ，McGeer AJ ，Mubareka S ，Falzarano D ... -  《Med-US》

Pre-Omicron Vaccine Breakthrough Infection Induces Superior Cross-Neutralization against SARS-CoV-2 Omicron BA.1 Compared to Infection Alone.

da Silva ES ，Kohnen M ，Gilson G ，Staub T ，Arendt V ，Hilger C ，Servais JY ，Charpentier E ，Domingues O ，Snoeck CJ ，Ollert M ，Seguin-Devaux C ，Perez-Bercoff D ... -  《INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES》

Neutralization of Omicron sublineages and Deltacron SARS-CoV-2 by three doses of BNT162b2 vaccine or BA.1 infection.

Kurhade C ，Zou J ，Xia H ，Liu M ，Yang Q ，Cutler M ，Cooper D ，Muik A ，Sahin U ，Jansen KU ，Ren P ，Xie X ，Swanson KA ，Shi PY ... -  《Emerging Microbes & Infections》

Vaccination and Omicron BA.1/BA.2 Convalescence Enhance Systemic but Not Mucosal Immunity against BA.4/5.

Diem G ，Jäger M ，Dichtl S ，Bauer A ，Lass-Flörl C ，Reindl M ，Wilflingseder D ，Posch W ... -  《Microbiology Spectrum》

Absence of neutralizing antibodies against the Omicron SARS-CoV-2 variant in convalescent sera from individuals infected with the ancestral SARS-CoV-2 virus or its Gamma variant.

The aim of the present study was to evaluate if neutralizing antibody responses induced by infection with the SARS-CoV-2 strain that was dominant at the beginning of the pandemic or by the Gamma variant was effective against the Omicron variant. Convalescent sera from 109 individuals, never exposed to a SARS-CoV-2 vaccine, who had mild or moderate symptoms not requiring hospitalization following either a documented SARS-CoV-2 ancestral strain infection or a Gamma variant infection, were assayed for in vitro neutralizing antibody activity against their original strains and the Omicron variant. Following an infection with the ancestral strain, 56 (93.3%), 45 (77.6%) and 1 (1.7%) serum sample were positive for neutralizing antibodies against the ancestral, Gamma variant, and Omicron variant, respectively. After infection with the Gamma variant, 43 (87.8%) and 2 (4.1%) sera were positive for neutralizing antibodies against the Gamma and Omicron variants, respectively. Neutralizing antibodies generated following mild or moderate infection with the SARS-CoV-2 ancestral strain or the Gamma variant are not protective against the Omicron variant.

Villas-Boas LS ，Paula AV ，Silva ARD Jr ，Paiao HGO ，Tozetto-Mendoza TR ，Manuli ER ，Leal FE ，Ferraz ABC ，Sabino EC ，Bierrenbach AL ，Witkin SS ，Mendes-Correa MC ... -  《-》