Flu vaccination underway to protect against all 20 influenza viruses

For half a century, scientists have been working to develop vaccines that protect people from the most dangerous influenza viruses.

Now, researchers at the University of Pennsylvania are taking a new approach, based on mRNA technology that has proven highly effective against COVID-19. Their idea is to target all 20 flu viruses with her single attack.

Their new vaccine won’t save us from needing an annual flu shot. can be protected from

Here’s what research has shown and what such vaccines can achieve:

Why was it so difficult to develop a universal influenza vaccine?

The annual flu shot protects against four types of influenza. However, strains circulating in people can vary greatly, so an entirely new vaccine is usually required each year to prevent serious illness.

And for 20 influenza viruses, a vaccine that protects against 4 strains may provide little protection against a pandemic caused by one of the other 16 influenza types. Influenza circulating in birds, pigs, and other animals can infect humans.

Most universal influenza vaccine efforts to date have attempted to target a portion of the virus present in many strains. did not provide

By targeting all 20 flu strains simultaneously, the scientists behind the new vaccine hope to offer at least some protection against all possible strains.

“We decided to put the entire kitchen sink into this vaccine,” said Scott Hensley, who led the study, published in Science.

What does this vaccine do that other vaccines have not?

It is impossible to target the full spectrum of influenza virus using conventional production methods. But an mRNA vaccine can contain at least 20 different antigens for essentially the same cost as a single vaccine, according to Hensley, a professor of microbiology at Penn’s Perelman School of Medicine.

The researchers were pleasantly surprised that their vaccine could effectively target so many different strains at once and generate an immune response against all of them at the same time, at least in animals. .

Allison Kelvin, a virologist at the University of Saskatchewan’s Office of Vaccines and Infectious Diseases, said, “It was very interesting to me to have 20 and a strong immune response to each.” . . “That’s something I didn’t think was possible.”

Mice and ferrets are used in influenza research because they can catch the same strains of influenza that we do, but the vaccine appeared to be as safe as a typical influenza vaccine.

It’s not yet clear how this vaccine will be used, Kelvin said. Alternatively, it may contain more than 20 strains.

How will this shot help limit the flu pandemic?

Scientists have long worried that influenza viruses could be passed from animals to humans, as happened with swine flu in 2009.

I’ve been relatively lucky in recent years. The flu death toll in the United States has ranged from 5,000 last year to more than 50,000 in both 2014 and 2017. 1918 flu.

Scientists want to be prepared in case another highly contagious and deadly strain emerges.

People generally have the best immune memory for the first strain of influenza they encountered as children. are likely to avoid severe illness from all H1 strains for the rest of their lives, but may be more vulnerable to other strains.

“Our childhood infection, our first exposure to the influenza virus, is crucial for influencing how we respond to other influenza strains later in life,” Hensley said. rice field.

So, during the 2009 H1N1 swine flu pandemic, older people who had H1 flu as children were less likely to get sick than those born after 1968, when the epidemic of that type stopped. .

“You don’t have to be at the mercy of the flu strain you encountered early in life,” Hensley said. “Rather than relying on chance, let’s create a vaccine that introduces all these antigens at the same time.”

Hensley hopes to eventually vaccinate young children against all 20 influenza subspecies before they turn five, providing them with broad immune memory for the rest of their lives. Studies have shown that vaccinating animals with malaria also provided broad protection.

The immune system is accustomed to processing dozens of viral proteins during infection, so such a vaccine should remain safe, Hensley said.

In theory, the same shot could also safely deliver antigens against measles, RSV and coronavirus.

“This is a long-term goal, to try to figure out the maximum number of antigens that can be included in these vaccines,” Hensley said. “Can we have 50 antigens or 100? These are some of the questions that I am currently working on in my lab.”

What do I need before this vaccine is available?

Researchers are testing an vaccine in nonhuman primates after showing it works well in mice and ferrets. Human trials could begin as early as next year.

Hensley said the initial trials will likely include no more than five strains of influenza, with more to come if the technology proves effective.

Regulators have never faced such broad-spectrum vaccines before and need to develop a framework for analyzing them, which could slow down the development process.

“While 20-valent vaccines may have manufacturing or regulatory challenges, this study represents an important proof-of-concept for multiplexing influenza vaccines,” said Beth Israel of Virology and Vaccines. said Dr. Dan Barouch, who directs the research center. Deaconess Medical Center in Boston, who was not involved in the work.

It would also be difficult to study 20 different vaccines, Kelvin said. For example, H4 influenza strains are not known to circulate in humans.

“I am for this type of approach,” she said. “I just want to have a proper discussion about how to regulate it.”

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