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New vaccine aims to protect against coronaviruses and their variants

The nanoparticle vaccine shows promise of protecting humans from coronaviruses even before said viruses make the leap from animal to human.

(CN) — As the super-infectious BA.5 variant of the virus that causes Covid-19 marches across the United States, researchers at Caltech have developed new type of vaccine that shows promise in providing protection against different types of coronaviruses without the need to be updated against new variants.

The research published in the July 5 issue of Science shows that the “mosaic nanoparticle” vaccine was able to offer a powerful spectrum of protection against several types of  viruses in trials that were conducted in mice and monkeys.

Specifically, the vaccine offered protections against Covid-causing variants and other respiratory viruses like SARS and MERS.

All of these viruses, known as betacoronaviruses, are a subset of coronaviruses that are known to cause infections in humans and animals, and the research shows that the recipients were protected against variants that were not included as part of the vaccine.

“Animals vaccinated with the mosaic-8 nanoparticles elicited antibodies that recognized virtually every SARS-like betacoronavirus strain we evaluated," said Alexander Cohen, one of the study's co-authors. “Some of these viruses could be related to the strain that causes the next SARS-like betacoronavirus outbreak, so what we really want would be something that targets this entre group of viruses. We believe we have that."

The vaccine functions by presenting the immune system with pieces of spike proteins from SARS-CoV-2, the virus that caused the Covid-19 pandemic, and seven other SARS-like betacoronavirus. This causes the body to produce a variety of cross-reactive antibodies, and the test animals also showed protection from an additional coronavirus that was not included in the original eight.

"SARS-CoV-2 has proven itself capable of making new variants that could prolong the global Covid-19 pandemic," said Pamela Bjorkman, the David Baltimore Professor of Biology and Bioengineering at Caltech.  "In addition, the fact that three betacoronaviruses — SARS-CoV, MERS-CoV, and SARS-CoV-2 — have spilled over into humans from animal hosts in the last 20 years illustrates the need for making broadly protective vaccines."

If proven successful in humans, this vaccine could be a huge breakthrough in helping fight future pandemics caused by these diseases, which present issues because it's impossible to accurately predict which viruses will evolve to infect humans.

“What we're trying to do is make an all-in-one vaccine protective against SARS-like betacoronaviruses regardless of which animal viruses might evolve to allow human infection and spread. This sort of vaccine would also protect against current and future SARS-CoV-2 variants without the need for updating," Bjorkman said.

The next step for this promising research is for Bjorkman and colleagues to take their mosaic-8 nanoparticle immunization into phase 1 clinical trials in humans.

This trial will mostly enroll people who have either already received a Covid-19 vaccine or have been infected with SARS-CoV-2. In preparation for the trial, the researchers are planning to perform preclinical animal model experiments to compare the immune responses of animals that received a current Covid-19 vaccine with animals that have not been infected with the virus or vaccinated.

Further research will be supported by the Coalition for Epidemic Preparedness Innovations (CEPI), which has pledged to provide up to $30 million in funding. UK-based deep-tech organization CPI will assist the project’s manufacturing efforts.

"We have talked about the need for diversity in vaccine development since the very beginning of the pandemic," says Dr. Richard J. Hatchett, CEO of CEPI. "The breakthrough exhibited in the Bjorkman lab study demonstrates huge potential for a strategy that pursues a new vaccine platform altogether, potentially overcoming hurdles created by new variants."

In a statement, Bjorkman thanked past collaborators for their support and expressed excitement at the upcoming trial.

“We are now thrilled to be working with CEPI and our colleagues at Oxford, Ingenza, and CPI to move this vaccine candidate into the clinic. We are very encouraged by preclinical results assessing the mosaic RBD nanoparticle approach, which has demonstrated advantages over current vaccines and traditional single RBD nanoparticle vaccine candidates,” Bjorkman said. “Our consortium has already combined its diverse skill sets to implement new ideas and scientific advances, and we look forward to continuing to work with our wonderful collaborators.”

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