A “universal” vaccine that protects against every strain of flu could be available in a few years, scientists said Thursday.

Doctors at the National Institute of Allergy and Infectious Diseases (NIAID) in Maryland developed the two-stage flu jab to fight off all strains of influenza for decades, putting an end to the current practice of yearly immunizations.

The study, published in Science Express, said mice, ferrets and monkeys were first injected with a vaccine made from a flu virus’ DNA. They then received a “booster” dose of a regular seasonal flu vaccine.

Scientists found that after the combined injections the animals made antibodies capable of neutralizing strains of the flu virus from over several years.

“This significant advance lays the groundwork for the development of a vaccine to provide long-lasting protection against any strain of influenza,” said NIAID Director, Dr. Anthony S. Fauci.

“A durable and effective universal influenza vaccine would have enormous ramifications for the control of influenza, a disease that claims an estimated 250,000 to 500,000 lives annually, including an average of 36,000 in the United States.”

Safety trials had already begun and scientists hoped the jab could be tested on patients in 2013.