| Demographic Group: | Resident persons aged >=50 years. |
| Numerator: | Respondents aged >=50 years who report having received an influenza vaccination within the previous year. |
| Denominator: | Respondents aged >=50 years who report having or not having an influenza vaccination within the previous year (excluding unknowns and refusals). |
| Measures of Frequency: | Annual prevalence — crude and age-adjusted (standardized by the direct method to the year 2000 standard U.S. population, master list) — with 95% confidence interval. |
| Time Period of Case Definition: | Previous year. |
| Background: | Although vaccination rates have increased, in 2002, only 68% of adults aged >=65 years were vaccinated against influenza. Influenza vaccination rates are even lower among adults aged 50–64 years. |
| Significance: | Each year in the United States, influenza infections result in an average of 36,000 deaths (>90% of deaths occur among adults aged >=65 years) and over 200,000 pneumonia and influenza hospitalizations. An annual influenza vaccination might prevent or attenuate the clinical course of respiratory illness attributable to influenza. With the aging of the population, increasing numbers of adults will be at risk for these diseases and their complications. To increase influenza vaccination among persons aged 50–64 years with medical conditions associated with increased risk of complications from influenza infection, the Advisory Committee on Immunization Practices has recommended that the age for annual influenza vaccination be lowered from age 65 years to 50 years. |
| Limitations of Indicator: | Respondents might not distinguish between influenza and pneumococcal (Streptococcus pneumoniae) vaccinations. Indicator does not measure vaccination rates among persons at high risk (e.g., persons with chronic illness) aged <50 years who should also be immunized. |
| Data Resources: | Behavioral Risk Factor Surveillance System (BRFSS).
http://apps.nccd.cdc.gov/brfss/ |
| Limitations of Data Resources: | As with all self-reported sample surveys, BRFSS data might be subject to systematic error resulting from noncoverage (e.g., lower telephone coverage among populations of low socioeconomic status), nonresponse (e.g., refusal to participate in the survey or to answer specific questions), or measurement (e.g., social desirability or recall bias). |
| Healthy People 2010 Objectives: | 14-29: Increase the proportion of adults (noninstitutionalized adults aged >=65 years) who are vaccinated annually against influenza and ever vaccinated against pneumococcal disease. (14-29a is specific for influenza vaccine.) |
