Seasonal flu vaccination rates among American adults have only slightly improved over last year, despite increased public discussion of the importance of influenza vaccines resulting from the worldwide outbreak of the H1N1 virus. The findings are from a national survey of more than 5,000 adults conducted online between November 4-16, 2009 about their vaccination status and related issues.
As of the middle of November, about 32 percent of all U.S. adults and 37 percent of adults recommended to receive a flu vaccination had been vaccinated against seasonal influenza, according to the survey. Adults recommended to receive a flu vaccination included in the survey were people 50 years of age and older, those with medical conditions that place them at risk for influenza complications (i.e., asthma, diabetes, heart disease, chronic lung disease), health care workers and those who are in close contact with people in high-risk categories. The U.S. Centers for Disease Control and Prevention (CDC) recommends the seasonal flu vaccine for about 70 percent of American adults, including these groups.
Among the unvaccinated, the survey also found that 17 percent of all adults and 19 percent of those specifically recommended for vaccination intend to receive the seasonal flu vaccine by the end of the flu vaccination season.
"It does not appear that the increased public discussion of the role of influenza vaccines has had a significant impact on the public's behavior," said Katherine Harris, the study's lead author and a senior economist at RAND, a nonprofit research organization. "Most of the results from our latest survey look much like those from last year."
One difference from last year noted by the new survey is that more adults began getting the flu vaccine earlier this year. Uptake of the seasonal vaccine during September was nearly three times as high -- about nine percent in 2009 versus three percent in 2008. Yet, overall vaccine uptake through mid-November this year was comparable to uptake during the same period last year, based on the percentage of respondents reporting vaccination.
In addition, about half of health care workers had been vaccinated by the middle of November this year, roughly the same proportion that was vaccinated during the entire influenza season last year. Nonetheless, 39 percent of health care workers reported they had no intention of being vaccinated despite the risk of transmitting influenza to patients.
"Health care workers are at the front lines of patient care, so it is critical for them to be vaccinated, not only for their own protection, but for their patients," said William Schaffner, MD, president-elect, National Foundation for Infectious Diseases (NFID) and Chairman of the Department of Preventive Medicine and Professor of Infectious Diseases in the Department of Medicine, Vanderbilt University. "These data also draw important attention to the fact that, despite overwhelming expert advice, they are not taking precautions against influenza."
Researchers say the survey was designed to help inform public health officials and others about progress toward vaccinating adults prior to the end of the vaccination season while action can still be taken to improve uptake. The survey is the latest in a series done by RAND and supported by GlaxoSmithKline, a manufacturer of flu vaccine.
The survey found seasonal influenza vaccine availability may be a 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 vaccinated.
"These findings highlight one of the public health challenges that we face in a year when a pandemic influenza virus has made an appearance," Harris said. "The early surge of uptake might be attributed to additional awareness about flu in a pandemic year. It's an important lesson that we need to keep in mind in planning for future pandemics."
Other findings 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 care 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 an influenza vaccine.
- Results showed that 44 percent of adults with a chronic disease surveyed have been vaccinated against the seasonal influenza this flu season. Additionally, just one-fifth of those surveyed plan to receive the influenza vaccine this flu season.
- White adults were more likely to have been vaccinated than other racial groups. Hispanic adults were the least likely racial group to have been vaccinated.
The study, "Seasonal Influenza Vaccine Use by Adults in the U.S. During the 2009-2010 Vaccination Season: A Snapshot as of Mid-November 2009," is available at www.rand.org. Other authors of the study are Jurgen Maurer and Lori Uscher-Pines.
Study reveals high effectiveness of flu vaccines in children but highlights challenges with certain subtypes