Association between immunoglobulin g levels and adverse effects following vaccination with the bnt162b2 vaccine among japanese healthcare workers

Abstract

The purpose of the study was to assess the association between the amount of immunoglob-ulin G (IgG) and the duration of adverse effects of COVID-19 vaccinations in the Japanese population. This cross-sectional study was conducted from April 2020 to August 2021 among workers at a community hospital. All participants received two doses of the BNT162b2 vaccine (Pfizer-BioNTech) in March and April 2021. Vaccine side effects were measured using a self-administered question-naire. Serum anti-SARS-CoV-2 IgG was measured 3 months after vaccination. There was a total of 338 participants (mean age: 44.7 years). The incidence of adverse reactions after vaccination was higher in women. Adverse reactions associated with higher IgG levels included: erythema at the injection site after the first dose; induration and inflammation at the injection site; and systemic symp-toms, e.g., fever and headache after the second dose. IgG levels were higher in younger participants. These findings could mitigate fears regarding the mild adverse effects of the COVID-19 vaccine and encourage uptake of the BNT162b2 vaccine.