Full and Partial Flu Vaccination Coverage in Young Children, Six Immunization Information Systems Sentinel Sites, 2012-13–2016-17

DATA SOURCE: Immunization Information Systems (IIS) data from IIS Sentinel Sites.

Footnote: Census data were used as denominators and IIS data from the six IIS Sentinel Sites were used as numerators. Full vaccination coverage was classified as having received at least the recommended number of flu vaccine doses (one or two), based on ACIP recommendations for that season. Partial vaccination coverage was classified as having received only one flu vaccine dose when recommended to receive two doses.

Influenza viruses can cause mild to severe illness, and severe influenza illnesses may result in hospitalization or death. The Advisory Committee on Immunization Practices (ACIP) recommends all children 6 months through 18 years receive annual influenza (flu) vaccination and children 6 months through 8 years receive two doses in their first vaccination season to achieve adequate immune response (1). Children who previously received flu vaccines may not require two doses in the current season; however, in some circumstances, two doses are still necessary, e.g., when a new strain is added to a flu vaccine. ACIP updates its flu vaccination recommendations each year and may recommend two doses to children even after their first flu seasons depending on their vaccination histories (2–8).

For this report, CDC analyzed data for >2.8 million children from six IIS Sentinel Sites for the 2012–13 through 2016–17 flu seasons, which was approximately 10% of the U.S. pediatric population. Full and partial flu vaccination coverage among children 6 months through 8 years is presented by age group and flu season.

Additional information on flu vaccination coverage for the United States is provided at FluVaxView as interactive maps, figures, and tables.

Key Findings

• In the 2016–17 flu season, full flu vaccination coverage was 47.4% in the 6–23-month group, 36.7% in the 2–4-year group, and 32.0% in the 5–8-year group.
• From the 2015–16 to the 2016–17 flu season, full flu vaccination coverage increased 2.4 percentage points in the 6–23-month group, but slightly declined in the 2–4-year (by 1.0 percentage point) and 5–8-year groups (by 1.1 percentage point).
• From the 2012–13 through 2016–17 flu seasons, flu vaccination coverage of ≥1 dose showed a declining trend in the first three seasons but slightly increased over the recent two seasons in the 6–23-month group. Flu vaccination coverage of ≥1 dose showed a slightly but consistently declining trend over all five seasons in the 2–4-year and 5–8-year groups.

In addition to efforts to increase flu vaccination coverage in general, the following efforts may improve two-dose compliance and thereby improve full vaccination coverage:

• Improved messaging of the two-dose flu vaccine recommendations is needed for providers and parents.
• Providers are encouraged to submit data to IIS to enhance the system and to use consolidated vaccination histories in IIS to assess children’s eligibility for two doses, especially for older children who may be perceived not to need two doses.

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Data Source & Methods

This is an update of data presented previously, and data source and methods have been described elsewhere (9).

Limitations

This analysis is subject to limitations. First, data from six IIS Sentinel Sites might not represent the U.S. population. Second, incomplete vaccination histories in IIS data may underestimate vaccination coverage and two-dose compliance, especially in older children who visit their physician’s office less frequently and may receive flu vaccination in other places. However, the child participation rate was >95% for each IIS Sentinel Site (10), which reduces potential underestimations of flu vaccination.

Authors (and affiliation)

Xia Lin¹, PhD, MSPH; Ramona Rai², MPH; Loren Rodgers¹, PhD

¹ Immunization Services Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA.

² TEKsystems, Atlanta, GA.

Related Links

General information about IIS and IIS Sentinel Sites:

• Immunization Information Systems (IIS)
• IIS Sentinel Sites

General information about flu:

• Influenza (Flu)
• Weekly U.S. Influenza Surveillance Report

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References/Resources

1. Centers for Disease Control and Prevention. Prevention and Control of Influenza: Recommendations of the Advisory Committee on Immunization Practices (ACIP), 2008. MMWR Recommendations and reports : Morbidity and mortality weekly report Recommendations and reports / Centers for Disease Control. 2008 Aug 8;57(RR07):1-60. Retrieved from https://www.cdc.gov/mmwr/preview/mmwrhtml/rr5707a1.htm.
2. Fiore AE, Uyeki TM, Broder K, Finelli L, Euler GL, Singleton JA, et al. Prevention and control of influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices (ACIP), 2010. MMWR Recommendations and reports : Morbidity and mortality weekly report Recommendations and reports / Centers for Disease Control. 2010 Aug 6;59(RR-8):1-62. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/20689501.
3. Centers for Disease Control and Prevention. Prevention and control of influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices (ACIP), 2011. MMWR Morbidity and mortality weekly report. 2011 Aug 26;60(33):1128-32. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/21866086.
4. Centers for Disease Control and Prevention. Prevention and control of influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices (ACIP)–United States, 2012-13 influenza season. MMWR Morbidity and mortality weekly report. 2012 Aug 17;61(32):613-8. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/22895385.
5. Centers for Disease Control and Prevention. Prevention and control of seasonal influenza with vaccines. Recommendations of the Advisory Committee on Immunization Practices–United States, 2013-2014. MMWR Recommendations and reports : Morbidity and mortality weekly report Recommendations and reports / Centers for Disease Control. 2013 Sep 20;62(RR-07):1-43. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/24048214.
6. Grohskopf LA, Olsen SJ, Sokolow LZ, Bresee JS, Cox NJ, Broder KR, et al. Prevention and control of seasonal influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices (ACIP) — United States, 2014-15 influenza season. MMWR Morbidity and mortality weekly report. 2014 Aug 15;63(32):691-7. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/25121712.
7. Grohskopf LA, Sokolow LZ, Olsen SJ, Bresee JS, Broder KR, Karron RA. Prevention and Control of Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices, United States, 2015-16 Influenza Season. MMWR Morbidity and mortality weekly report. 2015 Aug 7;64(30):818-25. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/26247435.
8. Grohskopf LA, Sokolow LZ, Broder KR, Olsen SJ, Karron RA, Jernigan DB, Bresee JS. Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2016–17 Influenza Season. MMWR Morbidity and mortality weekly report. 2016 Aug 26;65(5);1–54. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/27560619.
9. Lin X, Fiebelkorn AP, Pabst LJ. Trends in compliance with two-dose influenza vaccine recommendations in children aged 6 months through 8 years, 2010-2015. Vaccine. 2016 Sep 23. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/27670074.
10. Centers for Disease Control and Prevention. Immunization Information Systems Annual Report (IISAR) – IISAR participation rates and maps (2015). Retrieved from https://www.cdc.gov/vaccines/programs/iis/annual-report-iisar/rates-maps-table.html September 2017.

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