A COVID-19 nanoparticle vaccine: cost-effective and accessible
Scientists are currently developing a COVID-19 nanoparticle vaccine that, unlike currently approved and available COVID-19 vaccines, only requires a single dose, with no strict transport and storage requirements.
The COVID-19 pandemic has seen over 63 million confirmed cases and over 1 million deaths worldwide. Since the beginning of the pandemic, developing a safe and effective vaccine against SARS-CoV-2 – the coronavirus responsible for COVID-19 – has been a public health and research priority worldwide. For scientists at a laboratory at Stanford University in the US, biochemist Peter S. Kim and his team have redirected efforts from working on vaccines against Ebola, HIV and influenza to developing a vaccine against SARS-CoV-2. Since then, they have been able to design and test a promising new COVID-19 nanoparticle vaccine candidate. The details of their COVID-19 nanoparticle vaccine and its potential will be published in ACS Central Science.
The team's goal is to develop a single-dose vaccine that does not require a cold chain (a temperature-controlled supply chain for manufacture, transport, distribution and storage). While mRNA vaccines (like the currently approved Pfizer and Moderna vaccines) can be made quickly, they are expensive and require a cold chain, which can be problematic if properly stored and shipped to health care facilities. Virus-based vaccines (such as those made with an inactivated or weakened form of the virus), while very effective at generating a strong immune response, can be longer-lasting and more likely to have side effects. Nanoparticle vaccines like the COVID-19 nanoparticle vaccine developed by Kim and his team at Stanford University can be an attractive alternative because they are still effective and safe, while being easier and faster to make. This could make it a suitable inexpensive and accessible vaccination option, especially for low- and middle-income countries.
The scientists developed their COVID-19 nanoparticle vaccine using one of the spike proteins found on the SARS-CoV-2 virus and combined it with ferritin nanoparticles (an iron-containing blood protein). Two variants of the spike nanoparticle vaccine were developed – one with a full-length spike protein and one with a truncated spike protein – and tested in mice to assess immune responses. After a single dose of the COVD-19 nanoparticle vaccine with full or shortened spike, the immune response – as measured by neutralizing antibodies, which are produced in response to antigens and prevent virus invasion of host cells – was much higher than the response in people who were previously with Were infected with COVID-19. In particular, the shortened spike nanoparticle produced significantly higher neutralizing antibody levels compared to the full length spike nanoparticle version.
The COVID-19 nanoparticle vaccine is still in its early stages and the team is continuously working on improving its vaccine candidate as a single-dose vaccine that can be stored at room temperature. They are confident that advances in their COVID-19 nanoparticle vaccine will ultimately lead to initial human clinical trials. With several other vaccine candidates currently in their development and testing stages, the team is also ready to redirect the work effort to develop a vaccine that can be more widely used to protect against a wide variety of coronaviruses, including the well-known SARS . CoV-1, MERS and SAR-CoV-2 viruses.
Written by Maggie Leung, PharmD.
References
Powell, A. E., Zhang, K., Sanyal, M., Tang, S., Weidenbacher, P. A., Li, S.,. . . Kim, P.S. (2021). A single immunization with spike-functionalized ferritin vaccines triggers neutralizing antibody reactions against SARS-CoV-2 in mice. ACS Central Science. doi: 10.1021 / acscentsci.0c01405
Nanoparticle vaccine against COVID-19. (2021, January 8th). Retrieved from https://www.eurekalert.org/pub_releases/2021-01/su-nvf010821.php
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