Large-scale serosurveillance of COVID-19 in Japan: Acquisition of neutralizing antibodies for Delta but not for Omicron and requirement of booster vaccination to overcome the Omicron’s outbreak

Abstract

Continuous appearance of SARS-CoV-2 variants and mass vaccination have been intricately influencing on the COVID-19 situation. To elucidate the current status in Japan, we analyzed totally 2,000 sera in August (n = 1,000) and December (n = 1,000) 2021 collected from individuals who underwent a health check-up. The anti-N seropositive rate were 2.1% and 3.9% in August and December 2021, respectively, demonstrating a Delta variant endemic during that time; it was approximately twofold higher than the rate based on the PCR-based diagnosis. The anti-S seropositive rate was 38.7% in August and it reached 90.8% in December, in concordance with the vaccination rate in Japan. In the December cohort, 78.7% of the sera showed neutralizing activity against the Delta variant, whereas that against the Omicron was much lower at 36.6%. These analyses revealed that effective immunity against the Delta variant was established in December 2021, however, prompt three-dose vaccination is needed to overcome Omicron’s outbreak.

Global SARS-CoV-2 seroprevalence from January 2020 to April 2022: A systematic review and meta-analysis of standardized population-based studies

“…Our findings provide evidence of regional and temporal variation in the overall seroprevalence, over 80% in SEAR and AFR in late 2021 and over 90% in AMR HIC and EUR HIC in early 2022. In WPR, there was a paucity of high-quality population-based studies in 2021, and estimated seroprevalence was as low as 30.3% in December 2021, though 1 study in Japan suggests that this has increased to over 90% in February 2022 [ 43 ]. Regional variation is driven by differences in the extent of SARS-CoV-2 infection and vaccination.…”

Global SARS-CoV-2 seroprevalence: a systematic review and meta-analysis of standardized population-based studies from Jan 2020-May 2022

“…Our findings provide evidence of regional and temporal variation in the overall seroprevalence, over 80% in SEAR and AFR in late 2021 and over 90% in AMR HIC and EUR HIC in early 2022. In WPR, there was a paucity of high-quality population-based studies in 2021 and estimated seroprevalence was as low as 30.3% in December 2021, though one study in Japan suggests this has increased to over 90% in February 2022 [43]. Regional variation is driven by differences in the extent of SARS-CoV-2 infection and vaccination.…”

“…*Unity Studies Collaborator Group: Ximena Aguilera19 , Sheikh Al-Shoteri20 , Eman A Aly8 , Mauricio Apablaza 21 , Rosemary A Audu22 , Amal Barakat8,23 , Abdulla S Bin-Ghouth24 , Enyew Birru25 , Dejan Bokonjic 26 , Shelly Bolotin27,28 , Henry K Bosa29,30 , Emily L Boucher31 , Elma Catovic-Baralija32 , Alexei Ceban33 , Annie Chauma-Mwale34 , Judy Chen35 , Battogtokh Chimeddorj 36 , Pui Shan Chung 10 , Cheryl Cohen 37 , Tienhan S Dabakuyo-Yonli38 , Gabriel R Deveaux31 , Boly Diop39 , Titus H Divala40 , Emily K Dokubo41 , Irene O Donkor42 , Claire Donnici 31 , Nathan Duarte43 , Natalie A Duarte44 , Timothy G Evans7,14 , Lee Fairlie45 , Ousmane Faye46 , Gudrun S Freidl11 , Claudia González19 , Tiffany G Harris47,48 , Belinda L Herring 3 , Sopon Iamsirithaworn49 , Gloria Icaza 50 , Rhoda Ila 51 , Natasha Ilincic44 , Elsie A Ilori52 , Francis Y Inbanathan 9 , Vicki Indenbaum53 , John Kaldor54 , Dayoung Kim31 , Olatunji M Kolawole55 , Jambo C Kondwani56,57 , Tatiana Kuchuk 58 , Pritesh J Lalwani…”

Novel monoclonal antibodies showing broad neutralizing activity for SARS-CoV-2 variants including Omicrons BA.5 and BA.2.75

“…Our earlier study (Ren et al, 2022) also describes the ELISA performed. The optical density was measured at wavelength 405 nm (OD 405 ) by a microplate photometer (Multiskan™ FC, Thermo Fisher Scientific).…”