New mRNA vaccine targeting all known influenza strains shows promise

A new mRNA vaccine targeting all known influenza strains in a single injection shows great promise in animal studies and opens the door to a wide range of possibilities with vaccine technology, including the potential prevention of the next influenza pandemic. flu.

University of Pennsylvania researchers published their findings in the journal Science Thursday, showing that the vaccine produced high levels of antibody protection in mice and ferrets against all strains of flu, which could one day help pave the way for a universal flu vaccine.

Research is rapidly taking mRNA technology to new heights and building on advances made in the COVID-19 pandemic to accelerate development of new vaccine platform, which has already been used effectively by billions of people in the world.

“Our approach was to make a vaccine encoding each influenza subtype and lineage that we know of,” said Scott Hensley, an immunologist at the University of Pennsylvania in Philadelphia and one of the study’s lead authors.

“The goal was to establish a baseline level of immune memory that could then be recalled when a new pandemic strain emerges.”

Unlike seasonal flu vaccines that protect against circulating strains that exist every year, but offer little protection against strains that can spread from animals and trigger pandemics, such as H1N1 in 2009this vaccine could theoretically provide immunity against all new strains of influenza.

“We are still in preclinical testing at this stage, we are planning a phase 1 human study, but so far away from animal models, it appears that this vaccine has achieved our goal of inducing immune memory in general” , Hensley said.

“Imagine if the population were primed with this vaccine, what we might see is not necessarily protection against infection with new pandemic strains, but a reduction in hospitalizations and serious illnesses – and that is really our goal. major.”

While a potential vaccine could be years away as it has yet to successfully pass human trials, developing a flu shot that can target all 20 known strains of influenza A and B is a feat. amazing scientist.

“It really shows that we can use mRNA vaccines in ways that we really haven’t thought of before,” said Alyson Kelvin, a virologist at the Vaccine and Infectious Disease Organization at the University of Saskatchewan, who co-wrote an independent report perspective on studying science.

“This is just the start of where we can take mRNA-based vaccines.”

A registered nurse delivers a Pfizer COVID-19 vaccine to a frontline worker at Vancouver General Hospital in Vancouver in March 2021. The mRNA technology used in COVID vaccines has significant potential for other forms of disease. (Ben Nelms/CBC)

“The sky is the limit” with mRNA technology

Research is opening up a world of new possibilities with mRNA vaccine technology.

And it also brings hope of one day averting hundreds of thousands of flu hospitalizations and deaths around the world each year – if it passes clinical trials and regulatory approval.

“It’s a way to cover a huge family of viruses that cause a huge burden of disease around the world each year,” Kelvin said. “Additionally, there are continual threats of a new flu virus spreading. So that could cover not only what we are currently dealing with, but also what we don’t know.”

There are still key unanswered questions about the research and development of the vaccine to ensure it is safe and effective in clinical trials, Kelvin said, but the fact that animals were able to elicit strong and distinct immune responses to each strain is very promising.

“It really puts this strategy more than a foot in the door — I would say completely through the door — of clinical application,” said Gary Kobinger, director of the University of Texas Galveston National Laboratory who helped develop a Canadian-led Ebola vaccine.

“It’s one of those times when you see a science paper on animals and you know it could be in humans in what would be a short to medium timeframe,” he added. “So let’s see if it works. We all hope it does.”

The vaccine uses lipid nanoparticlesa successful mRNA vaccine delivery system developed by Canadian scientist Pieter Cullis and researchers at the University of British Columbia, to target all known flu strains circulating and perpetually infecting us every year.

WATCH | Harnessing the potential of the mRNA vaccine:

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Possibilities of mRNA vaccines beyond COVID-19

The breakthrough technology used to create the Pfizer and Moderna COVID-19 vaccines, mRNA, could also be used to produce vaccines against other diseases, including HIV, influenza and even cancer.

“The vaccine induces broad immunity in mice and ferrets that had never seen the virus before. This mimics how this vaccine might work in young children,” Hensley said.

“But we found that the vaccine can also induce these broad responses in animals that had previously suffered and recovered from influenza infection.”

This means that if the vaccine were found to be safe and effective in humans and successfully approved, its use would not only be limited in children who have never had influenza infection before. It could also be widely used in the general population, including older people who are often at higher risk for serious complications.

“I think we can expect to see vaccine developers go in all sorts of directions,” Kelvin said. “I can’t predict what it will be, but the sky is the limit for what will be done in the next couple of years.”

Hensley said researchers aren’t sure if the platform will even work in animals, given that potential issues can arise with so-called immunodominance hierarchies – where our immune system responds to certain strains more efficiently. that others.

“We didn’t find that, we found that this vaccine elicited antibodies at fairly equal levels for all coded antigens,” he said. “So that was an important finding.”

The fact that strong antibody immune responses have been shown against all 20 different flu strains is very encouraging, Kelvin said, because even though not all strains are circulating at the same time, it is possible for flu strains to spread. animals and drive a pandemic at any time.

“We know there will be another flu virus spillover with pandemic potential,” she said. “Are we keeping this vaccine on the shelf ready to use? Or is this something we want to consider allowing for more seasonal approaches?

However, there are major regulatory hurdles to approving such a large and complex vaccine, even if it passes clinical trials.

“The bigger question is how do you get this to people? Because what’s incorporated into the vaccine are targets for viruses that aren’t currently circulating in people,” Kelvin said.

“So when regulators look at how they’re going to assess a vaccine and approve it for human use, they want to make sure it’s safe and effective. Well, how effective are we going to say for this vaccine ?”

And while traditional influenza vaccines are already effective in preventing serious illness and death in the most vulnerable when successfully combined with circulating strains, widespread influenza vaccine adoption remains a major challenge.

WATCH | Flu and overloaded health system:

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Concerns grow over triple threat of respiratory disease surge

The Ontario Medical Association is urging people to wear masks indoors and get their flu and COVID-19 shots amid growing concern that a spike in flu cases could overwhelm a system healthcare that is already seeing an influx of RSV and COVID patients.

Less than 40% of Canadians chose to get the flu shot in 2020, according to the latest federal data, although it is recommended and available for all children over six months. In the United States, this number is a little higher at more than 50 percent.

And only one in five Canadians have received a COVID booster or completed a first round of vaccines in the past six monthswhile just over 10% of Americans opted for a bivalent booster dose targeting the dominant circulating subvariant of Omicron BA.5.

“That’s the reality,” Kobinger said. “You can have the best vaccine on the planet, but if no one wants it or takes it, there’s no point.”


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