Scientists say new flu vaccines with improved clinical efficacy and effectiveness are needed, according to a research published Wednesday in The Lancet Infectious Diseases.

The study found that seasonal flu shots prevent only about 59 percent of infections in adults. H1N1 shots prevent infection in 69 percent of adults under 65, and nasal sprays prevent infections in 83 percent of children under age 7, reported USA Today.

"Today's flu shot is like an iPhone 1.0," says study author Michael Osterholm from the Center for Infectious Disease Research and Policy of the University of Minnesota. "What we need is an iPhone 10.0."

Still, Osterholm recommends getting vaccinated.

Designing flu shots is often more complicated than other vaccines because the influenza virus mutates frequently, according to experts.

Every vaccine is made to match the germs circulating at certain period of time. That is why sometimes vaccines have a better match one year compared to another.

Currently, scientists are working on a "universal flu shot" to be developed within the next five years, reports USA Today.

But that is not the only improvement. According to the report, researchers are also looking to create flu shots in cell cultures rather than eggs, a way that speeds up the manufacturing process. Speed would be especially important in a scenario of a flu pandemic.

Scientists are also studying "adjuvants," ingredients that can be added to the flu vaccine for a stronger immune response. However the flu shots that are currently given in the United States don't have these.