1. Introduction
infection
CORONAVIRUS, INFECTION, CORONAVIRUS DISEASE 2019, SEVERE ACUTE RESPIRATORY SYNDROME
These authors contributed equally to this work.Despite the effectiveness and safety of COVID-19 vaccines, vaccine-induced responses decline over time; thus, booster vaccines have been approved globally. In addition, interest in natural compounds capable of improving host immunity has increased. This study aimed to examine the effect of Korean Red Ginseng (KRG) on virus-specific antibodies after COVID-19 vaccination. We conducted a 24 week clinical pilot study of 350 healthy subjects who received two doses of the COVID-19 vaccine and a booster vaccination (third dose). These subjects were randomized 1:2 to the KRG and control groups. We evaluated antibody response five times: just before the second dose (baseline), 2 weeks, 4 weeks, 12 weeks after the second dose, and 4 weeks after the third dose. The primary endpoints were changes in COVID-19 spike antibody titers and neutralizing antibody titers. The antibody formation rate of the KRG group was sustained higher than that of the control group for 12 weeks after the second dose. This trend was prominently observed in those above 50 years old. We found that KRG can help to increase and maintain vaccine response, highlighting that KRG could potentially be used as an immunomodulator with COVID-19 vaccines.Coronavirus disease 2019 (COVID-19), which is caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused significant morbidity and mortality worldwide and an ongoing global public health crisis [Recent studies have suggested that the effectiveness of COVID-19 boosters also tends to dwindle over time, with waning occurring 5–9 weeks after a booster vaccination [Korean Red Ginseng (KRG), derived from However, no study has examined whether KRG affects COVID-19 vaccine-induced immune response and protection. Therefore, this study aimed to investigate the effect of KRG on the humoral response of hosts who received two doses of COVID-19 vaccines and a booster vaccination (third dose) in Korea.