National Immunization Survey New Directions FEATURED SESSION F0, Programmatic Issues Track: Improving Our Tools and Strategies National Immunization Conference March 7, 2007 James A. Singleton, MS Chief, Assessment Branch Immunization Services Division National Immunization Program

NIS Team Assessment Branch, ISD/NIP Ellen Anderson, Pat Cummings, Natalie Darling, Cindy Knighton, Qian Li, Tammy Santibanez, Kate Shaw, Phil Smith, Karen Wooten, Larry Wilkinson National Center for Health Statistics Marcie Cynamon, Meena Khare National Opinion Research Center John Thompson & staff The findings and conclusions in this presentation have not been formally disseminated by the Centers for Disease Control and Prevention and should not be construed to represent any agency determination or policy

Outline Overview of NIS methods National coverage estimates New information, areas & ages Telephone survey challenges Research Directions Conclusions

Overview of NIS Methods

The National Immunization Survey Random digit dialing survey Primary coverage assessment tool for children aged 19-35 months Extremely large ongoing survey ~1,000,000 households/year identified ~34,000 households/year complete interview ~22,000 households/year used in analyses

NIS Methods Households with age eligible children are identified 3-4% of households screened Interview is conducted Permission to contact providers is obtained

NIS Methods Provider-verified immunization histories are collected Survey instruments are mailed to providers, who mail or fax back responses Information about provider collected Only provider-verified vaccinations are used for estimation of vaccine coverage

NIS Methods Sample data weighted to reflect population by sampling area, racial/ethnic group, mother’s education, and child’s age Households reporting interruption in service used to represent households without landline telephone coverage Assumes children with adequate provider data represent other sampled children for whom such data were not collected, within adjustment strata

Strengths of the NIS Comparability of methodology means results are comparable among states and urban areas over time Identifies areas, populations and factors associated with under-immunization Provider-verified results Very precise national level coverage estimates

NIS 2005 Highlights OMB approval to partially fund NIS with VFC funds NIS used to estimate VFC need New contractor (NORC) Smaller target sample size ~16,600 w/adequate provider data Half of sample collected 4th quarter Hurricanes Urban area rotations implemented

National Coverage Estimates

Estimated Vaccination Coverage, U.S., 2004 DTP/DT/DTaP, 4+ doses: 85.5 ±0.8% Polio, 3+ doses: 91.6 ± 0.7% MMR, 1+ dose: 93.0 ± 0.6% Hib, 3+ doses: 93.5 ± 0.6% 4:3:1:3 series: 82.5 ± 0.9% Diptheria, Tetanus, Pertusis 4+ DTP / DT / DTAP 3 Polio 3+ Polio 1 Measles, Mumps, Rubella 1+ MMR 3 Haemophilus influenzae type b 3+ Hib 3 Hepatitis 3+ Hep 1 Varicella 1+ VRC

Estimated Vaccination Coverage, U.S., 2004 Hep B, 3+ doses: 92.4 ± 0.6% 4:3:1:3:3 series: 80.9 ± 0.9% 1st time >80% Varicella, 1+ doses: 87.5 ± 0.7% 4:3:1:3:3:1 series: 76.0 ± 1.0% Used to measure HP2010 starting 2005 Diptheria, Tetanus, Pertusis 4+ DTP / DT / DTAP 3 Polio 3+ Polio 1 Measles, Mumps, Rubella 1+ MMR 3 Haemophilus influenzae type b 3+ Hib 3 Hepatitis 3+ Hep 1 Varicella 1+ VRC

Collecting New Information

NIS Special Purpose Supplements (Topical Modules) Subsamples of NIS survey can be asked special-purpose questions Insurance Status (2001-02) Day Care and Breast Feeding (2001-02) Attitudes and Beliefs (2001-02) Vaccine Safety (2003-04) Vaccine Shortage (2003-04) Childhood Influenza (2004)

New Data Collection Health Insurance Module New vaccines Part of core survey starting 2006 Estimate VFC eligibility & need New vaccines MMR-Varicella combination vaccine added to 2006 provider survey Add rotavirus vaccine 2007 SES Module (proposed) Additional questions on socioeconomic status of family to better understand disparities in coverage

State and Local Area Integrated Telephone Survey (SLAITS) Surveys of children or adults conducted using NIS sampling frame Managed by NCHS/CDC Can be used by states Link NIS data with other information National Survey of Children’s Health Children aged 0-17 years Conducted 2003-04 Planned 2007, n~2,000 per state

Sampling New Areas

NIS is More Than One Survey... Atlanta Seattle San Diego Phoenix El Paso San Antonio Dallas Memphis Nashville Indianapolis Detroit Cleveland Columbus Miami Jacksonville Los Angeles Santa Clara New Orleans Birmingham Houston Milwaukee Philadelphia Newark NYC Boston Baltimore DC Chicago

Areas Surveyed by NIS 50 states and 28 selected urban areas (1994 – 2004) Urban areas selected based on conditions in 1994 Would like to add new urban or rural areas beyond original 28 Make room for new areas by not over-sampling in equal number of original urban areas

Urban Area Rotation 22 non-grantee urban areas eligible 5 new areas/year, 5 of 22 rotate Biennial rotation NACCHO Task Force New: pop’n increase, low income, rural Rotate: high, stable coverage

2005 National Immunization Survey New Areas Rotated Areas Alameda Co, CA San Bernardino Co, CA Denver tri-County, CO St. Louis City/Co, MO Clark Co, NV Santa Clara Co, CA San Diego Co, CA Miami-Dade Co, FL Marion Co, IN Boston, MA

2006 National Immunization Survey New Areas Rotated Areas Fresno Co, CA Rural northern Co’s, CA Eastern Co’s, KS Rural southern Co’s, NM Allegheny Co, PA Jefferson Co, AL Los Angeles Co, CA Orleans Parish, LA Franklin Co, OH Davidson Co, TN

Rotation Process Update Modify selection & notification process Earlier timelines Broader input Identify counties with low coverage by combining NIS data across years Rotated urban areas can fund NIS sample in off-years

Assessing New Age Groups

Adolescent Survey No current national survey to monitor adolescent vaccination coverage 2004 pilot study of 13-15 year olds Planned survey 2006 Use NIS sample frame Conduct 3rd or 4th quarter Sample 13 year olds Provider record check Vaccines TdaP, Meningococcal conjugate varicella, HepB, HepA Human papilloma virus vaccine acceptability Health insurance/VFC eligibility determination

Adult Immunization Surveys Used NIS sample frame to survey: Ages 65+ in 2003 Ages 50-64 and 65+ in 2004 Assessed influenza & pneumococcal vaccination, herpes zoster Provides data on vaccination behavior not routinely available from other surveys

Challenges Facing Telephone Surveys

Increasing Population Not Reachable by Landline Telephone Prevalence of children by household telephone service, January – June 2005 NHIS (Blumberg et al., NHIS) 5.8% wireless service only 1.5% no phone service Research underway to assess potential bias in NIS estimates from exclusion of these households

NIS Response Rates Telephone survey response rates declined from 87% (1994) to 73% (2004) Largely due to increase in unresolved telephone numbers (no answer, answering machines, caller ID) Response rates vary by area (65%-83% in 2004), generally lower in urban areas Cost of survey increases as response rates decrease Response rate still high compared to other telephone surveys

Dealing with Declining Response Rates Non-response - how much does it matter? estimate potential bias in vaccine coverage Improve survey operations Incentives, advance letters, protocols Targeted sampling frames Multiple response modes Sampling frames for cell phones

Research Directions

Recent & Future Research (I) Timeliness of vaccination Racial/ethnic disparities Vaccine-specific analyses Factors associated with coverage SES, medical home, health insurance, VFC eligibility Parental vaccine safety concerns Estimation methodology

Recent & Future Research (II) Valid doses Combination vaccines County-level coverage estimation Coverage trends by birth cohort Use of Immunization Information Systems as dual sampling frame Household surveys in U.S.-affiliated jurisdictions where NIS not feasible

Conclusions

THE NIS… Is a critical evaluation tool for national & state immunization programs Will be used for annual assessment of vaccination coverage in adolescents Must address increasing prevalence of wireless only households and declining response rates

NIS Ad Hoc Session Wednesday, March 8 Noon-2pm Magnolia Room Update on recent developments Ask questions Discuss NIS issues Areas to sample

Extra Slides

14-22. Vaccine-specific Coverage Rates Among Pre-school Aged Children Percent 2010 Target Hep B (3+) DTP(3+)† MMR(1+) PCV7 (3+) Polio (3+) Includes 2002 Final Data. *Slide taken from Sudip Parik’s presentation, December 2002, presented by Walt Orenstein* Data checked by DMD, Lawrence Barker, May 28, 2003. Varicella (1+) Hib (3+) † DTP(3+) is not a Healthy People 2010 objective. DTP(4) is used to assess Healthy People 2010 objectives. Note: Children in the USIS and NHIS were 24-35 months of age. Children in the NIS were 19-35 months of age. Source: USIS (1967-1985), NHIS (1991-1993) CDC, NCHS, and NIS (1994-December 2004), CDC, NIP and NCHS; No data from 1986-1990 due to cancellation of USIS because of budget reductions

Estimated Vaccination Coverage, U.S., 2004 PCV7, 3+doses: 73.2 ± 1.0% Influenza, 6-23 mo., 2003-04* 1+ dose: 17.5% (16.5-18.7) Fully vaccinated: 8.4% (7.7-9.3) * Encouraged 2002-03 & 2003-04 seasons; recommended starting with 2004-05 season Diptheria, Tetanus, Pertusis 4+ DTP / DT / DTAP 3 Polio 3+ Polio 1 Measles, Mumps, Rubella 1+ MMR 3 Haemophilus influenzae type b 3+ Hib 3 Hepatitis 3+ Hep 1 Varicella 1+ VRC

NIS Non-Coverage and Non-Response Excludes households without landline telephones Non-response Not reached (no answer, answering machine) Reached, not screened Screened, deny age-eligible child Identify age-eligible child, interview incomplete Interview complete, no consent for PRC PRC consent, no provider response Provider response, IZ data inadequate

NIS-IIS Project (proposed 2006) In selected areas, use registry as sample frame in addition to RDD sample Usual provider record check Potentially more efficient way to reach households with 19-35 mo children Match RDD sample frame with registry how complete is registry frame how complete is registry IZ data non-response bias estimation using registry data for children in RDD sample with non-response at various levels