High Neutralizing Antibody Levels Against Severe Acute Respiratory Syndrome Coronavirus 2 Omicron BA.1 and BA.2 After UB-612 Vaccine Booster
Farshad Guirakhoo, Shixia Wang, Chang Yi Wang, Hui Kuo, Wen Jiun Peng, Hope Liu, Lixia Wang, Marina Johnson, Adam Hunt, Mei Mei Hu, Thomas P. Monath, Alexander Rumyantsev, David Goldblatt
Abstract
The highly transmissible severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant has caused high rates of breakthrough infections in those previously vaccinated with ancestral strain coronavirus disease 2019 (COVID-19) vaccines. Here, we demonstrate that a booster dose of UB-612 vaccine candidate delivered 7-9 months after primary vaccination increased neutralizing antibody levels by 131-, 61-, and 49-fold against ancestral SARS-CoV-2 and the Omicron BA.1 and BA.2 variants, respectively. Based on the receptor-binding domain protein binding antibody responses, the UB-612 third-dose booster may lead to an estimated approximately 95% efficacy against symptomatic COVID-19 caused by the ancestral strain. Our results support UB-612 as a potential potent booster against current and emerging SARS-CoV-2 variants.