For the longest time, people have been relying on annual flu shots to remain protected from the evolving virus come fall season. But things could change soon as scientists work on a new type of flu vaccine.

Last week, the National Institutes of Health (NIH) announced a clinical trial of an experimental universal influenza vaccine developed by researchers from the National Institute of Allergy and Infectious Diseases' (NIAID) Vaccine Research Center (VRC). The facility already started enrolling volunteers for the Phase 1 trial at Duke University in Durham, North Carolina.

According to the NIH, the trial will need up to 50 healthy individuals aged 18 to 49. They will be randomly assigned into different groups, each receiving a specific dose of the experimental vaccine. Data from the participants will then be evaluated to determine the optimum dosage of the vaccine.

The new vaccine is far from the typical flu shot released annually come fall season. It is designed to protect recipients from a wide variety of strains, ensuring better and more durable long-term immunity from the flu.

"A universal influenza vaccine would be a major public health achievement and could eliminate the need for both annual development of seasonal influenza vaccines, as well as the need for patients to get a flu shot each year," Acting NIAID Director Hugh Auchincloss, M.D., said.

"Moreover, some strains of influenza virus have significant pandemic potential. A universal flu vaccine could serve as an important line of defense against the spread of a future flu pandemic," he added.

The yearly flu shots target four selected strains in anticipation of the next flu season. The experimental vaccine is capable of targeting more strains because it uses the same mRNA technology used in making the COVID-19 vaccines from Pfizer and Moderna, according to Cleveland.com.

The annual flu shots are made using chicken eggs injected with different strains of the virus. The process involves choosing a portion of the virus that is highly variable between strains and changes year after year. The new vaccine focuses on a portion of the virus that is common across all strains, which explains why it is considered a "universal" shot.

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A similar vaccine developed by researchers at VRC already showed promising results in early clinical trials. Should the new clinical trial succeed, scientists could move closer to their goal of producing a more effective flu vaccine that does not need to be updated annually.

Though mostly mild for most people, seasonal influenza could also be deadly. In the U.S., thousands die of the flu each year. Based on data from the Centers for Disease Control and Prevention (CDC), between 12,000 and 52,000 people died of flu annually from 2010 to 2020. Experts urge the public to always get the updated vaccines ahead of the flu season.