Scientists Are Close To Inventing A Universal Flu Vaccine

Researchers are claiming progress toward developing a “universal” flu vaccine, which would combat all forms of the virus and provide the world with a weapon against future flu pandemics.
In an early clinical trial, scientists from the United States discovered that their experimental flu vaccine may induce recipients’ immune systems to manufacture “cross-reactive” antibodies. That is, they produced antibodies against a wide range of influenza A strains, one of the virus’s two primary groupings.
The findings were deemed promising by experts because the vaccine performed exactly as expected in this early stage of testing.
However, it has yet to be proven that it protects people from the flu, according to Sarah Andrews of the National Institute of Allergy and Infectious Diseases’ Vaccine Research Center.

She anticipated that if all goes well, it could take another five to ten years for the vaccine to be ready for use in the real world.

Currently, current flu vaccines prepare the body to fight four flu strains: two type A influenza strains and two type B influenza strains.

The trouble is that there are several strains within those two groupings, and different ones are prevalent during each flu season. As a result, the flu vaccination must be modified annually to incorporate the four types that experts believe will dominate in the forthcoming season.

It’s essentially a wild guess.

“And that guess isn’t always correct,” said Dr. Mirella Salvatore, an associate professor at Weill Cornell Medicine in New York City, and a spokeswoman for the Infectious Diseases Society of America.

Salvatore, who was not involved in the new study, believes that a universal flu vaccine would not only eliminate the yearly guessing game, but would also help prepare people for the next flu epidemic.

Several vaccines of this type are in various stages of development. According to Salvatore, the one Andrews and her colleagues are working on has now passed an early test.

“They’re showing it produces an antibody response, and the antibodies last a long time,” she said.

According to findings published April 19 in the journal Science Translational Medicine, one year after being vaccinated, study participants still had neutralizing antibodies against type A flu viruses.
There are several reasons why a universal flu vaccine has remained elusive, but the most significant is the intricacy of the influenza virus.

Andrews indicated that the new vaccine was created to circumvent a critical obstacle.

Current flu vaccinations comprise weakened or inactivated flu viruses as well as a mixture of hemagglutinins (HAs), a key protein on the virus’s surface. When patients acquire the flu or a flu vaccine, their immune systems produce antibodies against HA—specifically, antibodies against the top region, or “head,” of the protein.

That’s a concern since sections of the HA head frequently mutate, necessitating the yearly vaccination update.

But HA has more than just a head—it also has a “stem.” And that stem remains reasonably steady and “conserved” across flu strains.

Getting the immune system to respond to the stem, on the other hand, is difficult, according to Andrews. People’s immune systems have been conditioned by a lifetime of flu virus exposure to attack the HA head while ignoring the stem.

So Andrews and her colleagues took a novel approach: they severed the protein’s head. They then replaced it with a sort of manufactured top, meant to offer stem support while avoiding the immune system’s wrath.

“The only thing the immune system can see is the stem,” Andrews said.

The researchers recruited 52 healthy adults and gave each one of two vaccination doses to put the headless HA to the test in humans. The majority received the larger dose, which was administered as a primary injection followed by a booster shot.
First and foremost, the vaccination appeared to be safe, according to the researchers. One-fifth of those who had the flu vaccination experienced discomfort at the injection site or a headache, which are common adverse effects.
In terms of immunological response, individuals demonstrated a wide antibody response against type A flu viruses but not type B. Andrews noted that this was to be expected because the vaccine contains HA from a type A strain.

A “bivalent” vaccination (including HA from both influenza groups) would be expected to have “increased breadth,” according to the researchers.

Dr. Aaron Glatt, an infectious disease specialist who was not involved in the trial, concurred that the early immune responses appeared encouraging.
He compared the vaccine strategy to an ice cream cone. Instead of going after each of the 32 possible ice cream flavors, “you go after the cone,” said Glatt, chief of infectious diseases at Mount Sinai South Nassau in Oceanside, N.Y.
No one knows what the regimen will look like if a universal flu vaccine becomes available, according to Glatt. Would people have to receive it once a year or less frequently, for example?
Furthermore, it would not always prevent people from becoming ill. All of the experts agreed that a vaccination that significantly protects against severe flu would be beneficial.

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