Dr. William Schaffner, president-elect of the National Foundation for Infectious Diseases, said the finding that only 53 percent of adults have been vaccinated falls far short of the U.S. Centers for Disease Control and Prevention's goal of at least 70 percent, WebMD reported.

"Seventy percent of us adults should be vaccinated according to CDC's specific recommendations -- never mind that the CDC says everybody else should, too," Schaffner said at a news conference Thursday. "This looks like we are not doing very well, and must do better."

The RAND survey of about 4,000 U.S. adults shows that 53 percent have no plans to get the flu vaccine and 17 percent said they plan to but haven't yet.