Department of Pediatrics

Coronavirus Vaccines


The vaccine center's primary goal is to create effective, safe, and affordable vaccines with global accessibility. In our pursuit of coronavirus vaccines, we employ recombinant receptor binding domain (RBD) protein antigens that can be easily produced on a large scale.  

Our vaccine technology utilizes the versatile yeast expression system to produce recombinant proteins, which are then adjuvanted with aluminum plus other immunostimulants. For our coronavirus program,  we have waived patent protections, enabling partners, governments and/or manufacturers in developing nations to gain easy access to expand production and facilitate distribution to all segments of their populations.

Yeast-based recombinant protein vaccines, a proven approach against coronavirus outbreaks

Beginning in 2011, we embarked on efforts to develop coronavirus vaccines, becoming one of the first groups to recognize their pandemic threats. With the New York Blood Center and the University of Texas Medical Branch, we developed two recombinant subunit vaccine technologies for SARS and MERS-CoV. Both the SARS and MERS vaccine candidates protected mice from lethal infections. For the SARS-CoV RBD219-N1 vaccine candidate, a batch of clinical-grade drug substance was generated at WRAIR. The SARS and MERS vaccines remain as part of our research & development efforts as possible components of a multivalent pan-coronavirus vaccine.

In 2020, our RBD-based vaccine technology targeting SARS-CoV-2 showed promising results in various preclinical testing models and successfully progressed manufacturing and the clinic, where it exhibited safety, immunogenicity, and efficacy. Leveraging our vaccine technology, two human vaccines—Corbevax by Biological E Ltd in India and Indovac by Bio Farma in Indonesia—were manufactured for less than $2 per dose and administered extensively, surpassing 100 million doses combined in India and Indonesia alone. In 2024, Corbevax received Emergency Utilization Listing from the WHO.  


Ongoing Research Activities


XBB.1.5 RBD/alum/CpG

Continued research includes vaccines targets with updated RBD variants of SARS-CoV-2.  Our partner in India, Biological E, is currently advancing our latest SARS-CoV-2 vaccine technology, featuring the XBB 1.5 RBD antigen [13], which demonstrated effective cross-neutralization against the recent omicron subvariants, such as JN.1.


Developing broad-spectrum coronavirus vaccines is crucial for readiness against future respiratory virus pandemics. New data showcased broad neutralization through a trivalent subunit vaccine, combining the RBDs of SARS-CoV, MERS-CoV, and SARS-CoV-2 XBB.1.5 with Alum and CpG. Mice vaccinated with this trivalent vaccine generated cross-neutralizing antibodies against all three human Betacoronaviruses, as well as some viruses currently still confined to bats, suggesting the preservation of epitopes in the individual antigens during co-formulation and the potential for epitope expansion. 


Selected Coronavirus Review papers:


Hotez, P. J. et al. Calling for rapid development of a safe and effective MERS vaccine. Microbes Infect 16, 529–531 (2014). Pubmed

Hotez, P. J., Corry, D. B., Strych, U. & Bottazzi, M. E. COVID-19 vaccines: neutralizing antibodies and the alum advantage. Nat Rev Immunol 20, 399–400 (2020). Pubmed

Hotez, P. J. & Bottazzi, M. E. Whole Inactivated Virus and Protein-Based COVID-19 Vaccines. Annu Rev Med 73, 55–64 (2022). Pubmed

Pollet, J., Chen, W.-H. & Strych, U. Recombinant protein vaccines, a proven approach against coronavirus pandemics. Adv Drug Deliv Rev 170, 71–82 (2021). Pubmed

Hotez, P. J. et al. From concept to delivery: a yeast-expressed recombinant protein-based COVID-19 vaccine technology suitable for global access. Expert Rev. Vaccines 22, 495–500 (2023). Pubmed

SARS-CoV Coronavirus Research Papers:

Chen, W.-H. et al. Yeast-expressed recombinant protein of the receptor-binding domain in SARS-CoV spike protein with deglycosylated forms as a SARS vaccine candidate. Hum Vaccin Immunother 10, 648–658 (2014). Pubmed

Chen, W.-H. et al. Optimization of the Production Process and Characterization of the Yeast-Expressed SARS-CoV Recombinant Receptor-Binding Domain (RBD219-N1), a SARS Vaccine Candidate. J Pharm Sci 106, 1961–1970 (2017). Pubmed

Chen, W.-H. et al. Yeast-expressed SARS-CoV recombinant receptor-binding domain (RBD219-N1) formulated with aluminum hydroxide induces protective immunity and reduces immune enhancement. Vaccine 38, 7533–7541 (2020). Pubmed

MERS-CoV Coronavirus Research Papers:

Nyon, M. P. et al. Engineering a stable CHO cell line for the expression of a MERS-coronavirus vaccine antigen. Vaccine 36, 1853–1862 (2018). Pubmed

SARS-CoV-2 Coronavirus Research Papers:

Pino, M. et al. A yeast expressed RBD-based SARS-CoV-2 vaccine formulated with 3M-052-alum adjuvant promotes protective efficacy in non-human primates. Sci. Immunol. 6, (2021). Pubmed

Pollet, J. et al. Receptor-binding domain recombinant protein on alum-CpG induces broad protection against SARS-CoV-2 variants of concern. Vaccine 40, 3655–3663 (2022). Pubmed

Pollet, J. et al. SARS‑CoV-2 RBD219-N1C1: A yeast-expressed SARS-CoV-2 recombinant receptor-binding domain candidate vaccine stimulates virus neutralizing antibodies and T-cell immunity in mice. Hum. Vaccines Immunother. 17, 2356–2366 (2023). Pubmed

Thimmiraju, S. R. et al. A Recombinant Protein XBB.1.5 RBD/Alum/CpG Vaccine Elicits High Neutralizing Antibody Titers against Omicron Subvariants of SARS-CoV-2. Vaccines 11, 1557 (2023). Pubmed