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A volunteer gets the experimental universal flu vaccine in Bethesda, Maryland. Image via NIAID

The National Institutes of Health (NIH) is on a quest to develop a vaccine that could provide long-term immunity to all types of the flu.

This year up to 36 million people have gotten the flu, about 500,000 have been hospitalized for the flu, and there’ve been up to 46,800 deaths since October 2018, according to the Centers for Disease Control and Prevention (CDC).

And this flu season has been relatively mild, thanks to this year’s highly effective vaccine. The vaccine has cut people’s chances of getting the flu by about half, a substantial improvement from last year’s shot.

Not to mention, flu activity continues to be widespread in 34 states plus Puerto Rico, and there’s a more severe strain on the rise across the country.

Clearly, while the vaccine has gotten better, it’s far from perfect.

Now the NIH is looking for to see if a vaccine can guard against nearly all strains of the flu virus.

The first-ever universal influenza vaccine is currently being tested in people at the NIH Clinical Center in Bethesda, Maryland, the NIH announced Wednesday.

“The hope is that [the vaccine] will target more strains, and if we’re really lucky, most or all strains. This is important because the current vaccine is a best-guess version in anticipation of the coming flu season, which often leads to a vaccine that does not cover all strains that actually materialize,” Dr. David Mushatt, an infectious disease specialist and section chief of infectious diseases at Tulane University, told Healthline.

The first clinical trial will evaluate the vaccine’s safety and tolerability in addition to its ability to trigger an immune response in the body.

Researchers will recruit at least 53 healthy adults between the ages of 18 and 70 years who will be injected with the experimental vaccine. There will be two groups: The first group will receive a single, lower-dose injection. The second group — which will be broken into subgroups based on age — will receive two higher-dose injections spaced 16 weeks apart.

The research team will then monitor the participants over the next 12 to 15 months to evaluate how their bodies respond to the vaccine.

The researchers hope to understand how age and previous exposure to different influenza strains may influence the participants’ immune responses to the experimental vaccine.

Attached to the surface of the flu virus are little tubes, known as the hemagglutinin (HA) protein. The HA is composed of a head region and a stem region. The head region sticks out above the virus’s body, while the stem is mostly hidden under the head and within the body of the virus.

The current flu vaccines are designed to treat the head region, causing our immune systems to detect and make antibodies against the head of the virus.

However, the head frequently mutates, or changes, which prevents the immune system from detecting the HA and knowing it’s time to take action.

“The reason someone comes down with the flu is that their immune system doesn’t recognize the HA. The flu strains that circulate each season are the ones that people’s immune systems don’t recognize,” Dr. Richard Rupp, a professor of pediatrics and director of the Sealy Institute for Vaccine Sciences at the University of Texas Medical Branch, told Healthline.

The new, experimental vaccine will focus on the body’s immune response to the stem region instead. According to Rupp, the stem rarely changes from year to year and is essentially the same in several strains.

Because the stem is more constant than the head across most influenza strains, the vaccine is less likely to need to be updated each season, the NIH said.

“The candidate universal vaccine being tested here could cover multiple flu strains, and it is possible it wouldn’t be necessary to vaccinate every year, since the protection provided by the vaccine might cover the different variant viruses year to year,” Dr. Mark Mulligan, the director of infectious diseases and immunology at NYU Langone Health, said.

While this vaccine will hopefully provide us with long-lasting protection against many types of the flu, it probably won’t eliminate the flu entirely, health experts predict.

For one, the vaccine will only target type A strains, which covers the influenza strains that circulate seasonally and cause epidemics, according to Mushatt.

There are also influenza type B, C, and D infections, all of which do not typically cause pandemics.

“It likely won’t target all strains, but it could target a higher number of strains and variants, and therefore be more broadly protective against the different flu strains,” Mulligan explained.

Furthermore, because the flu has animal reservoirs, such as birds and pigs, there’s always a chance that a new version of the influenza A strain could pop up.

Lastly, to eliminate the influenza A strains, nearly everyone worldwide would need to be vaccinated — a number much higher than what we’ve been able to achieve thus far.

As a result, flu cannot be eradicated, says Mulligan, but it can be controlled, reduced, and prevented.

The National Institutes for Health announced it’s testing the first-ever universal influenza vaccine. The experimental vaccine will focus on the immune responses to part of the flu virus that doesn’t change much year to year and is the same across many strains of flu.

While this won’t eradicate the flu, health experts hope the new vaccine will provide longer-lasting protection against most types of the flu.