Technically Speaking: Some Surprising Findings in the 2021 National Immunization Survey-Teen (NIS-Teen)

On Sept. 2, 2022, the Centers for Disease Control and Prevention (CDC) published the results of the annual random-dialed telephone survey that estimates vaccination coverage among 13- to 17-year-olds, commonly referred to as the NIS-Teen. When preparing the report, “National Vaccination Coverage among Adolescents Aged 13–17 Years — National Immunization Survey-Teen, United States, 2021,” the research team does not just take parents’ reports of immunization, but, after the interview, they ask for permission to contact the adolescents’ vaccination providers. These providers are mailed a request for the adolescents’ vaccination records. About 2 out of 5 adolescents with completed interviews had adequate provider data to allow for inclusion in the analysis.

Have you had a chance to review this year’s results yet? They had some surprises. See if you know the answers to the following questions related to the 2021 NIS-Teen:

1. Which coverage rates increased between 2020 and 2021?

1. ≥ 2 doses of MenACWY vaccine among 17-year-olds
2. ≥ 1 dose of HPV vaccine among 13- to 17-year-olds
3. Up-to-date HPV vaccination, according to predefined age and dose recommendations among 13- to 17-year-olds
4.  All of these

The answer is D. Coverage rates increased for each of these:

• ≥ 2 MenACWY doses among adolescents aged 17 years improved from 54.4% to 60.0%.
• ≥ 1 dose of HPV vaccine increased from 75.1% to 76.9% among 13- to 17-year-olds.
• Up-to-date HPV vaccination, according to predefined age and dose recommendations, rose from 58.6% to 61.7%.

2. For which of these vaccine doses did the coverage rate remain stable from 2020 to 2021?

1. ≥ 1 dose of Tdap 
2. ≥ 1 dose MenACWY 
3. ≥ 2 doses MMR
4. History of varicella or ≥ 2 doses of vaccine
5. All of these

The answer is E. Coverage for each of these remained stable overall for 13- to 17-year-olds.

3. Which findings suggest continued effects from the pandemic?

1. Lower Tdap coverage (≥ 1 dose) among children who turned 12 during the pandemic, compared with those who turned 12 before the pandemic.
2. Lower MenACWY coverage (≥ 1 dose) among children who turned 13 during the pandemic, compared with those who turned 13 before the pandemic.
3. Both of these.
4. Neither of these.

The answer is C. Coverage with ≥ 1 Tdap dose dropped by 4.1 percentage points and coverage with ≥ 1 MenACWY dose dropped by 5.1 percentage points.

4. With respect to immunization coverage, did adolescents living at or above the poverty level fare the same regardless of the type of community in which they lived (i.e., urban vs. rural)?

1. Yes
2. No

The answer is B. Adolescents in rural areas fared worse than those living in urban areas. Specifically, compared with adolescents aged 13-17 years living in metropolitan statistical areas (MSA), coverage in rural areas was lower for numerous measurements:

• 9.0 percentage points lower for ≥ 1 HPV vaccine dose
• 8.8 percentage points lower for predefined up-to-date HPV vaccination
• 3.0 percentage points lower for ≥ 1 MenACWY dose
• 6.9 percentage points lower for ≥ 2 HepA doses

Also, for those 17 years of age, coverage with ≥ 2 MenACWY doses was 11.8 percentage points lower for those living in rural, compared with urban, areas.

5. Which racial/ethnic group had the lowest coverage for Tdap (≥ 1 dose) and MenACWY (≥ 1 or ≥ 2 doses)?

1. Non-Hispanic White
2. Non-Hispanic Black
3. Hispanic
4. American Indian/Alaska Native
5. Asian
6. Non-Hispanic Multiracial

The answer is C. See “Supplemental Table 1” for data comparing vaccine coverage by race and ethnicity.

6. Adolescents with which type of insurance coverage had the highest rates of HPV vaccine coverage, but not necessarily other vaccines?

1. Private insurance only
2. Any Medicaid
3. Other insurance
4. No insurance

The answer is B. See “Supplemental Table 2” for data comparing vaccine coverage by type of insurance.

Conclusions

I have been a pediatrician long enough to remember when improving access was considered the cure for suboptimal vaccination coverage. This no longer appears to be the case. As we reach the asymptotes of vaccination coverage curves, we will need new approaches to improve vaccination coverage. I suspect that Vaccine Education Center’s readers are at the forefront of forging new paths.