The severity of influenza varies from year to year with about 3,000 to 49,000 influenza-related deaths occurring each year. Annual influenza vaccination is the best method of protection against influenza and its complications. The Advisory Committee on Immunizations Practices recommends annual influenza vaccination for all persons 6 months and older. The Healthy People 2020 influenza vaccination targets are annual coverage of 80 percent for persons 6 months to 64 years and 90 percent for adults 65 years and adults 18-64 years with high-risk conditions or living in long-term care facilities and nursing homes.
To provide national mid-season estimates of influenza vaccination coverage and behaviors and opinions regarding influenza vaccines during the 2011-12 influenza season, the Centers for Disease Control and Prevention (CDC) conducted the National Flu Survey (NFS) during Nov. 1-13, 2011. The NFS will be conducted again in March 2012 to provide rapid end-of-season influenza vaccine coverage estimates. This report describes national estimates of the proportion of people vaccinated by approximately Nov. 6, 2011, using results from the November 2011 NFS.
Key findings are as follows:
- Many children and adults remained unvaccinated by the first week of November; 36.3 percent of people 6 months and older, 36.7 percent of children, and 36.2 percent of adults had already received influenza vaccination by this time.
- These estimates are higher for children and similar for adults compared to coverage estimates from the November 2010 NFS and suggest that overall vaccine uptake for the 2011-12 is on track with the 2010-11 season.
- Estimated coverage among Hispanic and non-Hispanic other race children were higher when compared to non-Hispanic white children, and coverage for non-Hispanic black and white children was similar. These preliminary results suggest that we have sustained the increased coverage among Hispanic and non-Hispanic black children seen during the 2010-11 season. However, as in prior seasons, influenza vaccination coverage among adults was higher for non-Hispanic whites compared to other racial and ethnic groups.
- Results from the March 2011 NFS showed a 10 percent increase in coverage estimates to 42.3 percent among all persons 6 months when compared to the November 2010 results from November 2010 through the end of the 2010-11 season. If the trend continues this season, overall coverage will still remain substantially below the Healthy People 2020 influenza vaccination targets.
- Influenza vaccinations should continue throughout the influenza season. Additional efforts are needed by medical providers and other immunization providers to enhance access and increase community demand for influenza vaccination, particularly among those at higher risk of severe complications from influenza, including young children, people of any age with high-risk medical conditions, and older adults.
- Among adults 18 years, estimated vaccination coverage was 36.2 percent, similar to this time last season.
- Among adults 18 to 64 years, estimated coverage was 30.9 percent for all persons in this age group, 3.7 percentage points higher than at this time last season.
- Estimated vaccination coverage in adults 18 to 64 years with at least one high-risk condition was similar to last year at 41.5 percent.
- Estimated vaccination coverage in adults 18-64 years without a high-risk condition was 27.3 percent, a 4.3 percent gain over last year.
-Among adults 65 years, estimated vaccination coverage was 62.3 percent, similar to coverage at this time last season.
- Among children 6 months to 17 years, coverage estimates were comparable among non-Hispanic whites (33.5 percent) and non-Hispanic blacks (35.5 percent)
- Among children 6 months to 17 years, estimated coverage among Hispanic (43.4 percent) and non-Hispanic other or multiple race (43.6 percent) children was higher compared to non-Hispanic white children (33.5 percent).
- Estimated coverage for Hispanics was 15.6 percentage points higher than this time last year.
Place of Vaccination
- The most common place of vaccination among both children (63.3 percent) and adults (31.6 percent) was a doctors office. Other medically-related places were also common places of influenza vaccination for children (26.9 percent) and adults (23.2 percent). Other common places of influenza vaccination reported for adults included pharmacies or stores (21.0 percent) and workplace (16.3 percent).
Knowledge of Influenza Vaccination Recommendation
- When asked which groups are recommended to get the flu vaccine, only 50.8 percent of adults responded correctly that influenza vaccination was recommended for all people six months and older. Vaccinated adults were more likely to know that the vaccine was recommended for all individuals six months or older (60.9 percent) than unvaccinated individuals (45.1 percent).
Public Health Implications
- Although many adults (36.2 percent) and children (36.7 percent) had already been vaccinated against influenza by the first week of November 2011, many more still need to be protected.
- Although the majority (58 percent) of persons vaccinated during the 2010-2011 season received their influenza vaccinations before the first week of November, 23 percent of vaccinated persons received their vaccination during November and 19 percent during December throughMay. Influenza vaccinations are still taking place and should continue throughout the flu season.
- Influenza activity in the United States does not typically peak until January or February and influenza activity was low as of the third week in November. Therefore, it is not too late to get vaccinated.
- Those who intend to get vaccinated should be vaccinated as soon as possible before influenza activity increases. It takes approximately two weeks for protective antibody to reach optimal levels after vaccination.
- Results from the March 2011 NFS showed a 10 percent increase in coverage estimates among all persons 6 months when compared to the November 2010 results. If this trend continues this season, coverage rates will again fall well below all Healthy People 2020 objectives for influenza vaccination. Continued efforts are needed to increase vaccination coverage rates of all individuals by enhancing access and increasing community demand for influenza vaccination.
- Strong recommendations by providers for their patients to get vaccinated are effective in increasing patient acceptance of vaccination. Providers are encouraged to recommend and offer influenza vaccination to their patients throughout the influenza season.
- Providers who do not offer influenza vaccination in their clinic should refer their patients to vaccine providers in their community.
- Standing orders, client reminder and recall systems, and provider reminders are also important strategies proven to increase vaccination uptake.
The November NFS is designed to provide rapid estimates of national influenza vaccination coverage and to assess the effectiveness of current immunization efforts. Additionally, the NFS is a useful tool for assessing how vaccination coverage so far this season compares to vaccination coverage by the same time last season.
The NFS will be conducted again in March 2012 to provide rapid end-of-season influenza vaccine coverage estimates.