From developing vaccines for Ebola, HIV, and pandemic influenza, biochemist Peter Kim and his team at the lab of Stanford University have now turned their attention to developing a vaccine for SARS-CoV-2, the virus that causes COVID-19.
Stanford News reports even though the coronavirus was outside the specific area of expertise at the Stanford laboratory, the team has managed to devise and test a potential vaccine candidate.
Kim said their goal for this new project is to develop a single-shot vaccine that does not need a "a cold-chain for storage or transport."
If successful with the development, the biochemist, also the Professor of Biochemistry at the Virginia and DK Ludwig said, their coronavirus vaccine should be affordable, too, as the target populations for this project are low- and middle-income countries.
Vaccine Containing Nanoparticles
The Stanford lab researchers' vaccine, detailed in a paper ACS Central Science published on January 5, contains nanoparticles studded with similar proteins comprising the distinctive surface spikes of the virus.
As specified in the study, nanoparticle vaccines balance the efficacy of "viral-based vaccines with the safety and ease-of-production of subunit vaccines."
Vaccines utilizing viruses to deliver the antigen are frequently more effective compared to those that contain only the secluded parts of a particular virus.
Nevertheless, they can take longer to produce, should be stored in a cold-chain, and are the potential to cause side effects.
Essentially, nucleic vaccines such as Pfizer and Moderna mRNA vaccines, both that have recently been authorized by the US Food and Drug Administration for emergency use, are even faster to produce compared to nanoparticle vaccines. However, they are costly to manufacture and may need multiple doses to work effectively.
Only a Single Dose Needed
Preliminary tests in mice propose that the Stanford nanoparticle vaccine could yield COVID-19 immunity after just a single dose.
The study authors are hopeful, too, that their vaccine could be stored at room temperature. They are investigating, too, if it could be transported and "stored in a freeze-dried, powder form."
By comparison, COVID-19 vaccines that are farthest along in development in the US are all required for storage in cold temperatures, ranging from roughly eight to 90 degrees Celsius.
According to the paper's lead author Abigail Powell, a former postdoctoral scholar in the Kim lab, their work is certainly in the early stage, and a lot of work still needs to be done.
However, she added, they think their research is a solid starting point for what could be "a single-dose vaccine regimen" that does not depend on the use of a virus to produce protective antibodies after vaccination.
The Stanford researchers are continuing to enhance and fine-tune their COVID-19 vaccine candidate, along with the intention of moving it closer to preliminary clinical trials in humans.
Abridged Spike and Nanoparticles Combined
The spike protein from SARS-CoV2 is quite large. Thus, scientists frequently develop abridged versions that are easier to make and use.
After closely evaluating the spike, the Stanford team opted for the removal of a section close to the bottom. For the completion of their vaccine, the researchers combined this abridged spike with nanoparticles of ferritin, a protein that contains iron, which has been previously tested in humans.
For the tests in mice, they had their shortened spike nanoparticles compared to four other possibly useful variations, including "nanoparticles with full spikes, full spikes or partial spikes minus nanoparticles," and a vaccine with only the section of the spike that binds to cells during infection."
Testing the efficacy of these vaccines to fight the actual SARS-CoV-2 virus would have necessitated the work to be conducted in a Biosafety Level 3 lab, so the researchers utilized a safer pseudo-coronavirus instead that was altered to carry the spikes of SARS-CoV-2.
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