Estimated Influenza Vaccination Coverage among Adults and Children — United States, September 1, 2004– February 27, 2005 BRFSS 2004–05 Gary L. Euler, DrPH Epidemiology and Surveillance Division National Immunization Program

Co-authors from NIP and NCCDPHP NIP Susan Chu, PhD Carolyn Bridges, MD Cedric Brown, MS Peng Jun Lu, PhD Mary McCauley, MTSC James Singleton, MS Shannon Stokely, MPH NCCDPHD Michael Link, PhD Ali Mokdad, PhD Laurie Elam-Evans, PhD Lina Balluz, ScD William Garvin Bill Bartoli Machell Town, MS Michele Sussman-Walsh Kathryn O’Neill David Gilbertz

BRFSS influenza vaccination questions in past years of adults only CORE 1.During the past 12 months have you had a flu shot? 2.During the past 12 months have you had a flu vaccine that was sprayed in your nose? OPTIONAL MODULE 1.Where did you go to get your most recent [FILL: flu shot/vaccine that was sprayed in your nose /vaccination ( whether it was a shot or spray in the nose)]?

BRFSS influenza questions added November–February 2004–05 for adult and child: 1.During what month and year did you receive your most recent flu vaccination? 2.Where did you go to get recent flu vaccination? 3.What is the main reason you have not received a flu vaccination for this current flu season? 4.Did you get a flu vaccination during the last flu season? 5.Has a doctor, nurse, or other health professional ever said that you have any of the following health problems? 6.Do you still have [FILL: this problem/any of these problems]?

BRFSS influenza questions added during November–February 2004–05 for adults 7.Do you currently work in a health care facility, such as a medical clinic, hospital, or nursing home? 8.Do you have direct face-to-face or hands-on contact with patients as a part of your routine work?

Purpose of BRFSS questions added November 2004 through February 2005 To measure/track ongoing influenza vaccination coverage/doses administered among priority and non-priority adult and child populations, nationally and by state. To measure main reasons for not being vaccinated, i.e., shortage-related? To determine to what extend ACIP/CDC prioritization was being implemented. To help guide policy and shape messages to state health departments, medical/public health professionals and the general public.

Adult influenza vaccination coverage September–February 2004–05 BRFSS* (n = 26,649) Populationn%95% CI † Aged ≥65y 6, ± 2.1 Aged 18-64y, high-risk § 4, ± 2.6 Health-care workers with patient contact 1, ± 4.0 Initial priority adults ¶‡ 12, ± 1.7 Healthy aged 50-64y 9, ±1.9 Healthy aged 18-49y 5, ±1.8 Initial nonpriority adults 14, ± 0.9 *Interviews conducted February 1- 27, 2005 † Confidence interval § Asthma; other lung, heart, or kidney problems; diabetes, weakened immune system, anemia, or pregnancy ¶ Persons can be included in more than one priority group. ‡ Includes persons in households with children aged <6m.

Child influenza vaccination coverage September–February 2004–05 BRFSS* (n = 6,591) Populationn %95% CI † Aged 6-23m ±9.8 Aged 2-17y, high-risk § ±7.0 Priority children1, ±6.6 Nonpriority children ¶ 5, ±1.8 *Interviews conducted Feb † Confidence interval § Asthma; other lung, heart, or kidney problems; diabetes, weakened immune system, anemia, or aspirin therapy. ¶ Includes persons in households with, and out-of-home care givers of, children aged <6m, and others with rare high-risk conditions.

Monthly influenza vaccination cumulative coverage among selected priority U.S. populations, BRFSS * *Interviews were conducted during February 1-27, † Does not include persons in households with children aged <6m, out-of-home care givers of children aged <6m, or others with rare high-risk conditions. § Asthma; other lung, heart, or kidney problems; diabetes, weakened immune system, anemia, or aspirin therapy. ¶ Asthma; other lung, heart, or kidney problems; diabetes, weakened immune system, anemia, or pregnancy. † § ¶ †

Proportion by month of season’s total doses received among selected priority U.S. populations, BRFSS * *Interviews were conducted during February 1-27, † Does not include persons in households with children aged <6m, out-of-home care givers of children aged <6m, or others with rare high-risk conditions. § Asthma; other lung, heart, or kidney problems; diabetes, weakened immune system, anemia, or aspirin therapy. ¶ Asthma; other lung, heart, or kidney problems; diabetes, weakened immune system, anemia, or pregnancy. † § ¶ †

Main reason stated for not receiving influenza vaccination, United States, BRFSS 2004 (Interviews Dec 1-11) n = 1,994 1, , ,340 *Includes concerns about vaccine, lack of access, and other reasons. ** Also includes not told by MD, thought flu not serious, and had flu already. HR = High risk. HCW = health-care worker with patient contact.

Main reason stated for not receiving influenza vaccination, United States, BRFSS 2005 (Interviews Jan 2-22) n = 4,747 2,669 1,204 10, ,340 *Includes concerns about vaccine, lack of access, and other reasons. ** Also includes not told by MD, thought flu not serious, and had flu already. HR = High risk. HCW = Health-care worker with patient contact.

Main reason stated for not receiving influenza vaccination, United States, BRFSS 2005 (Interviews Feb 1-27) n = 2,249 2, , ,479 *Includes concerns about vaccine, lack of access, and other reasons. ** Also includes not told by MD, thought flu not serious, and had flu already. HR = High risk. HCW = Health-care worker with patient contact.

Estimate of doses administered based on respondent- reported influenza vaccination coverage for current and past seasons BRFSS 2004–05 *Two questions: ‘past 12 m’ & ‘month/year’ ^One question: ‘during past season’

Percent of U.S. adults aged ≥65 years reporting influenza vaccination “during the past 12 months” by month of interview, BRFSS 3 selected seasons* *The coverage line for the season is shown here for comparison to the season because it was also a vaccine shortage season. The line for the season was used for comparison because it was the most recent season with adequate vaccine supply to reach demand.

Influenza Vaccination Coverage by Priority Groups, BRFSS 2004–05 Compared to NHIS m 36m 7m 6m 8m 56m 105m 47m Approximate population size in millions ?? ? No Data

Conclusions — 1 Vaccination coverage among adults in priority groups closely approached that achieved in previous years. Coverage among adults not in priority groups was about half the level in High numbers of adults choosing to forgo vaccination resulted in having enough vaccine to meet last-season-level of demand among priority persons. Very high uptake among children aged 6- 23m (52.2%).

Conclusions — 2 Firsts made possible by BRFSS 2004–05 : –Vaccination coverage and related data from early during the influenza season, allowed policy makers, officials, providers and public ‘real-time’ information for decisions regarding distribution and usage of the limited supply of vaccine. –National estimates provided of influenza vaccination coverage among children aged 2–17 years with HR conditions. –Month and year of influenza vaccination collected by a national surveillance system

Limitations — 1 Land-line telephone-based survey excludes segments of population Self-reported data Recall bias Institutionalized and caretakers not included February interviews miss vaccinations occurring later in the month

Limitations — 2 Comparison of data from BRFSS 2004–05 to 2003 NHIS is limited –Past 12 month question –In-person interviews Prior to 11/04 BRFSS did not ask about most of the priority groups