key: cord-0753346-vsc4b025
authors: Kitabatake, M.; Ouji-Sageshima, N.; Sonobe, S.; Furukawa, R.; Konda, M.; Hara, A.; Aoki, H.; Suzuki, Y.; Imakita, N.; Nakano, A.; Fujita, Y.; Shichino, S.; Nakano, R.; Ueha, S.; Kasahara, K.; Muro, S.; Yano, H.; Matsushima, K.; Ito, T.
title: Transition of antibody titers after the SARS-CoV-2 mRNA vaccine in Japanese healthcare workers
date: 2021-12-31
journal: nan
DOI: 10.1101/2021.12.28.21268435
sha: 07b896f43caf5c985bf79fb3d63d523af98b9814
doc_id: 753346
cord_uid: vsc4b025

Since February 2021, health care workers in Japan have been preferentially vaccinated with a messenger RNA vaccine (BNT162b2/Pfizer) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). While many studies have confirmed that this vaccine is highly effective in reducing hospitalizations and deaths from coronavirus disease 2019 (COVID-19), antibody titers tend to decline at 3 months, leading to a risk of breakthrough infections. Thus, information is needed to support decision making regarding the third vaccination. In this study, we investigated transition of the anti-SARS-CoV-2 receptor-binding domain (RBD) IgG and neutralizing antibody titers of 41 vaccinated Japanese healthcare workers. Samples were collected seven times starting 1 week before vaccination until 6 months post-vaccination. Anti-SARS-CoV-2 RBD IgG levels peaked at 7 days after the booster, then declined over time and decreased to <10% at 6 months after the booster. Workers with low anti-SARS-CoV-2 RBD IgG levels also had low neutralizing antibody titers. These data support the active use of boosters for healthcare workers, especially for those with low anti-SARS-CoV-2 RBD IgG levels.

The efficacy and safety of the BNT162b2 mRNA coronavirus disease 2019 vaccine (Pfizer-BioNTech, Mainz, Germany) has been widely demonstrated 1 . Real-world data on BNT162b2 have confirmed that this vaccine is highly effective in reducing laboratory-confirmed and community-acquired infections, viral loads in infected individuals, and COVID-19-related hospitalizations and deaths 2,3 . However, breakthrough infections have been reported in fully vaccinated persons 4 . Healthcare workers are potentially at a higher risk of infection owing to prolonged and repeated exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected patients 5 . A recent study reported that among fully vaccinated health care workers, the occurrence of SARS-CoV-2 breakthrough infections was correlated with neutralizing antibody titers during the peri-infection period 3 . Another study found that patients' humoral responses were substantially decreased 6 months after receiving the second dose of the BNT162b2 vaccine 6 . In this study, we evaluated the transition of antibody titers from the SARS-CoV-2 mRNA vaccine in 41 Japanese healthcare workers and the relationship between anti-SARS-CoV-2 receptor-binding domain (RBD) IgG levels and neutralizing antibody titers 6 months after the workers received the second BNT162b2 vaccine.

All rights reserved. No reuse allowed without permission. perpetuity. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in The copyright holder for this this version posted December 31, 2021. ; https://doi.org/10.1101/2021.12.28.21268435 doi: medRxiv preprint

Forty-one healthcare workers at Nara Medical University in Japan who had received the Pfizer-BNT162b2 vaccine between 10 March and 30 March 2021 were invited to participate as volunteers in the study. Participants provided peripheral blood samples for serologic assays before receiving the first vaccine, 1 week after receiving the first vaccine, then 1 week, 1 month, 3 months, and 6 months after receiving the second vaccine. All study participants provided written informed consent. Eligibility criteria were that participants were ≥20 years of age and had no history of suspected clinical SARS-CoV-2 infection. The Nara Medical University Ethics Committee approved the study (No. 3168). Additionally, other than for the humoral response, data are lacking regarding cell-All rights reserved. No reuse allowed without permission. perpetuity. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in

The copyright holder for this this version posted December 31, 2021. ; https://doi.org/10.1101/2021.12.28.21268435 doi: medRxiv preprint

1.351 Variants

BNT162b2 mRNA Covid-19 Vaccine in a Nationwide Mass Vaccination Setting

Waning of IgG, Total and Neutralizing Antibodies 6 Months Post-Vaccination with BNT162b2 in Healthcare Workers. Vaccines (Basel)

Covid-19 Breakthrough Infections in Vaccinated Health Care Workers

We thank Ms. Hisayo Nishikawa (Department of Immunology, Nara Medical University), for their assistance. We also thank Traci Raley, MS, ELS, from Edanz (https://jp.edanz.com/ac) for editing a draft of this manuscript.