New COVID-19 vaccines that don’t require refrigeration: They come from plants and bacteria

The new refrigerator-free vaccine is still in the early stages of development

"The exciting thing is that our vaccine technology is thermally stable, so it can easily reach places where ultra-low temperature freezers are impossible, without having to let trucks run around in these freezers," Nicole Steinmetz Say

A paper published in the Journal of The American Chemical Society on September 7 details these vaccines

Researchers have created two vaccine candidates for COVID-19

Both vaccines use similar formulations

The researchers pointed out several advantages of using plant viruses and bacteriophages to make vaccines

Another huge advantage is that plant viruses and phage nanoparticles are very stable at high temperatures

The goal is to give people more options for the COVID-19 vaccine and make it more accessible

"Imagine if vaccine patches could be sent to the most vulnerable people in our mailbox, instead of letting them leave their homes and risk exposure," said Professor Jon Pokorski at the Jacobs School of Nanoengineering at the University of California, San Diego, His team has developed techniques to make implants and microneedle patches

Pokolski added: “If the clinic can provide implants for one injection for those who are difficult to get a second injection, it will provide protection for more people and we will also have a better chance to stop it.

In the test, the team's COVID-19 vaccine candidate was injected into mice through implants, microneedle patches, or two consecutive injections

pan-coronavirus vaccine

Researchers found that these antibodies can also neutralize the SARS virus

It all comes down to the coronavirus spike protein attached to the surface of the nanoparticle

"The fact that the neutralization of epitopes so well-preserved in another deadly coronavirus is so profound is worth noting," said co-author Matthew Shin, who is from the Steinmetz Lab PhD student in nanoengineering

Another advantage of this particular epitope is that it is not affected by any SARS-CoV-2 mutations reported so far

Oscar Ortega-Rivera, a postdoctoral researcher in the Steinmetz laboratory and the first author of the study, explained that these mutations are unlikely to occur in epitopes from non-binding regions

Ortega Rivera said that this means that the new COVID-19 vaccine may be effective against the variants that are concerned, for example, testing is currently underway to see what effect they have on the Delta variant
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Ready-to-use vaccine

Another thing that excites Steinmetz is that this vaccine technology provides the versatility to make new vaccines
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Steinmetz said: "Even if this technology has no impact on COVID-19, it can quickly adapt to the next threat, the next X virus
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"

She said that the production of these vaccines is "plug and play": plant viruses or phage nanoparticles from plants or bacteria, and then attach a piece of the target virus, pathogen or biomarker to the surface of the vaccine
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"We use the same nanoparticles, the same polymers, the same equipment, and the same chemical methods to put everything together
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The only variable is the antigen that sticks to the surface
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"

The resulting vaccine does not require refrigeration
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They can be packaged as implants or microneedle patches
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Alternatively, it can also be injected directly in a traditional way
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Steinmetz and Pokorski’s laboratories have used this formula in previous studies to make vaccine candidates for diseases such as HPV and cholesterol
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Now they have proven that this method is also suitable for making COVID-19 vaccine candidates
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Next step

These vaccines still have a long way to go before entering clinical trials
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In the next step, the team will test whether these vaccines can prevent COVID-19 and its variants and other deadly coronavirus infections in the body
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Original search:

Trivalent subunit vaccine candidates for COVID-19 and their delivery devices

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