Immunizations: Influenza

Narrative

Influenza is a contagious respiratory illness that can have mild to severe effects. Older people, young children, pregnant women, and people with certain health conditions are at higher risk for serious flu complications, possibly resulting in hospitalization or death. To avoid potentially serious complications, the Advisory Committee on Immunization Practices (ACIP) recommends seasonal flu vaccination for everyone 6 months of age and older.1 In 2014, ACIP voted to recommend a preference for using the nasal spray flu vaccine instead of the flu shot in healthy children 2–8 years of age when it is available.2 The Healthy People 2020 target vaccination rate for children aged 6 months through 17 years is 70 percent.3

The overall proportion of children aged 6 months to 17 years who were vaccinated during the 2013–2014 flu season was 58.9 percent, which represented a 2.3 percentage point increase in coverage over the previous year. Vaccination rates held steady at around 75 percent during this timeframe, however, for children aged 6 to 23 months, representing a successful achievement of the Healthy People 2020 goal for that age group. In contrast, children aged 2–17 years did not meet the Healthy People 2020 goal. The proportion of children vaccinated for seasonal influenza decreased with age, falling to 46.4 percent among children aged 13–17 years (Figure 1).

seasonal flu vaccinations by age

Figure 1 Source

During the 2013–2014 flu season, the proportion of children aged 6 months to 17 years who received influenza vaccination varied by race and ethnicity, ranging from 55.2 percent of non-Hispanic White children to 70.6 percent of non-Hispanic Asian children (Figure 2). The proportion of children vaccinated was higher among all races and ethnicities compared to non-Hispanic White children, with the exception of non-Hispanic Black children (57.2 percent). In the 2013–2014 flu season, non-Hispanic American Indian/Alaska Native, Hispanic, and non-Hispanic White children showed increases in vaccination rates compared to the previous flu season.

Children in families with household incomes above 100 percent of poverty but below $75,000 had the lowest rate of vaccination (54.0 percent) in the 2013–2014 flu season. Children in families with incomes less than 100 percent of poverty or above $75,000 had similar rates of vaccination (62.8 and 60.8 percent, respectively).

seasonal flu vaccinations by race

Figure 2 Source

The 2013–2014 vaccination rates among children living in nonmetropolitan statistical areas (MSA) were lower (52.6 percent) than those in MSAs (62.6 and 58.9 percent for central city and non-central city, respectively). Children living in MSAs showed an increase in vaccination rates over the previous flu season, while children in non-MSAs did not.

Flu vaccination is the most effective strategy against the flu and serious flu-related complications. Multifaceted strategies are required to increase vaccination rates:

  1. Use of evidence-based practices (e.g., reducing client costs for vaccination; provision of immunizations at schools and Women, Infants, and Children programs; home visits; client reminder/recall; standing orders; provider reminders),4
  2. Nontraditional settings for vaccination (e.g., pharmacy, workplace, school venues),5 and
  3. Utilizing immunization information systems at the point of clinical care and to guide clinical/public health vaccination decisions.6

Data Sources

Figure 1. U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Immunization Survey – Flu. Accessed September 18, 2014.

Figure 2. U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Immunization Survey – Flu. Accessed September 18, 2014.

Endnotes

1 Centers for Disease Control and Prevention. Prevention and control of influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices, 2010. MMWR. August 6, 2010;59(RR08):1–62. Accessed September 23, 2013.+

2 Centers for Disease Control and Prevention. Advisory Committee on Immunization Practices (ACIP) recommends a preference for using the nasal spray flu vaccine. Accessed February 16, 2015.

3 U.S. Department of Health and Human Services. Healthy People 2020: Immunization and Infectious Diseases. Accessed August 20, 2013.

4 The Community Guide. Increasing Appropriate Vaccination. Accessed August 12, 2013.

5 Murphy PA, Frazee SG, Cantlin JP, Cohen E, Rosan JR, Harshburger DE. Pharmacy provision of influenza vaccinations in medically underserved communities. Journal of the American Pharmaceutical Association. 2012;52(1):67–70.

6 Murphy PA, Frazee SG, Cantlin JP, Cohen E, Rosan JR, Harshburger DE. Pharmacy provision of influenza vaccinations in medically underserved communities. Journal of the American Pharmaceutical Association. 2012;52(1):67–70.

Data

Statistical Significance Test

Calculate the difference between two estimates:

Calculated Z-Test Result 0.9567433 Not statistically significant

We follow statistical conventions in defining a significant difference by a p-value less than 0.05 where there is a less than 5% probability of observing a difference of that magnitude or greater by chance alone if there were really no difference between estimates. The 95% confidence interval includes a plausible range of values for the observed difference; 95% of random samples would include the true difference with fewer than 5% of random samples failing to capture the true difference.

This website allows comparisons between two estimates using the independent z-test for differences in rates or proportions. This test is appropriate for comparing independent populations across years (e.g., 2011 versus 2012) or subgroups (e.g., Male versus Female) on corresponding measures. To the extent possible, the functionality of this application has limited estimate comparisons based on appropriate use of the independent z-test. However, some tables present subgroup categories within broader categories that will allow comparisons between non-independent populations (e.g., low birth weight and very low birth weight). Users should exercise caution when interpreting these test results, which will frequently overstate statistical significance.

For some tables, the website does not allow for comparisons between two estimates, even though the data represent independent populations. Generally, this is because the standard errors were not publicly available at the time this website was created.

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