AUTHOR=Tran Thi Nhu Mai , May Bruce Pearson , Ung Trong Thuan , Nguyen Mai Khoi , Nguyen Thi Thuy Trang , Dinh Van Long , Doan Chinh Chung , Tran The Vinh , Khong Hiep , Nguyen Thi Thanh Truc , Hua Hoang Quoc Huy , Nguyen Viet Anh , Ha Tan Phat , Phan Dang Luu , Nguyen Truong An , Bui Thi Ngoc , Tu Tieu My , Nguyen Thi Theo , Le Thi Thuy Hang , Dong Thi Lan , Huynh Trong Hieu , Ho Phien Huong , Le Nguyen Thanh Thao , Truong Cong Thao , Pham Hoang Phi , Luong Cong Y. , Y Nie Lim , Cao Minh Ngoc , Nguyen Duy Khanh , Le Thi Thanh , Vuong Duc Cuong , Nguyen Le Khanh Hang , Do Minh Si 

TITLE=Preclinical Immune Response and Safety Evaluation of the Protein Subunit Vaccine Nanocovax for COVID-19

JOURNAL=Frontiers in Immunology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2021.766112

DOI=10.3389/fimmu.2021.766112

ISSN=1664-3224

ABSTRACT=<p>The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global health concern. The development of vaccines with high immunogenicity and safety is crucial for controlling the global COVID-19 pandemic and preventing further illness and fatalities. Here, we report the development of a SARS-CoV-2 vaccine candidate, Nanocovax, based on recombinant protein production of the extracellular (soluble) portion of the spike (S) protein of SARS-CoV-2. The results showed that Nanocovax induced high levels of S protein-specific IgG and neutralizing antibodies in three animal models: BALB/c mouse, Syrian hamster, and a non-human primate (<italic>Macaca leonina</italic>). In addition, a viral challenge study using the hamster model showed that Nanocovax protected the upper respiratory tract from SARS-CoV-2 infection. Nanocovax did not induce any adverse effects in mice (<italic>Mus musculus</italic> var. albino) and rats (<italic>Rattus norvegicus</italic>). These preclinical results indicate that Nanocovax is safe and effective.</p>