The study found that 29 percent of adults stated that they did not have the time to get vaccinated. In addition, seasonal flu vaccine availability may be a significant reason more adults have not been vaccinated. Among those intending to be vaccinated, about 38 percent said there was no vaccine available when they tried to get inoculated.

"This finding highlights one of the public health challenges that we face in a year when a pandemic flu has made an appearance," Harris said. "The early surge of uptake was attributed to additional awareness about seasonal flu vaccination in a pandemic year. It's important to keep this early interest in mind when planning for future pandemics."

Other finding from the study include:

There was little evidence that people were forgoing seasonal influenza vaccine in order to be vaccinated against H1N1.

Health care providers were widely seen as the best source of information about vaccinations. About 44 percent of vaccinated adults said their health provider was the most influential source of information; unvaccinated adults were less reliant on health care providers and more reliant on news reports than those who had received a flu vaccine.

White adults were more likely to be vaccinated than other racial groups. Hispanic adults were the least likely to have received a seasonal flu vaccine. Source: RAND Corporation