Table 2. Components of difference* between 2016 and 2017 NIS-Child estimates

Overall Difference (n = 30,321) Difference among Non-Overlapping Cohort (n = 11,173) Difference among Bridging Cohort (n = 19,148)

Vaccine/Dose

UTD by

19 to 35 months

% (95% CI)

UTD by

19 months

% (95% CI)

UTD during

19–34 months

% (95% CI)

UTD by

19 to 35 months

% (95% CI)

UTD by

19 months

% (95% CI)

UTD during

19–34 months

% (95% CI)

UTD by

19 to 35 months

% (95% CI)

UTD by

19 months

% (95% CI)

UTD during

19–34 months

% (95% CI)

DTaP†

≥3 doses 0.3 (-0.8–1.4) 0.6 (-0.8–1.9) -0.2 (-1.0–0.5) -1.0 (-2.7–0.6) 1.1 (-0.8–3.0) -2.2 (-3.1–1.2) 1.1 (-0.3–2.5) 0.2 (-1.5–1.9) 0.9 (-0.2–1.9)

≥4 doses -0.2 (-1.9–1.5) 1.1 (-1.0–3.3) -1.3 (-3.0–0.4) -8.3 (-11.1–5.5) 2.5 (-1.1–6.2) -10.8 (-13.9–7.8) 4.5 (2.3–6.6) 0.3 (-2.3–3.0) 4.1 (2.1–6.2)

Poliovirus (≥3 doses) 0.8 (-0.5–2.1) 1.2 (-0.4–2.7) -0.4 (-1.4–0.6) -1.1 (-3.1–0.8) 2.2 (-0.4–4.8) -3.3 (-5.1–1.5) 1.8 (0.2–3.4) 0.6 (-1.4–2.6) 1.2 (0.0–2.4)

MMR (≥1 dose) 0.4 (-0.9–1.7) 0.9 (-0.6–2.4) -0.5 (-1.4–0.4) -3.2 (-5.1–1.3) 0.4 (-2.0–2.9) -3.6 (-5.3–2.0) 2.4 (0.7–4.0) 1.1 (-0.7–3.0) 1.3 (0.2–2.3)

Hib§

Primary series 0.0 (-1.2–1.3) 0.4 (-0.9–1.7) -0.4 (-0.9–0.2) -0.9 (-2.7–0.8) 1.0 (-1.0–2.9) -1.9 (-2.8–1.1) 0.5 (-1.1–2.1) 0.0 (-1.7–1.8) 0.5 (-0.3–1.3)

Full series -1.1 (-2.9–0.7) 0.3 (-1.7–2.3) -1.4 (-2.6–0.3) -5.6 (-8.6–2.7) 1.0 (-2.3–4.3) -6.6 (-8.5–4.7) 1.5 (-0.8–3.7) -0.1 (-2.6–2.4) 1.6 (0.1–3.1)

HepB

≥ 3 doses 0.9 (-0.5–2.4) 1.2 (-0.3–2.7) -0.3 (-0.9–0.4) 0.1 (-2.1–2.2) 2.2 (-0.1–4.5) -2.1 (-3.1–1.1) 1.4 (-0.5–3.2) 0.6 (-1.4–2.6) 0.8 (-0.1–1.7)

Birth dose¶ 2.5 (0.3–4.8) 2.5 (0.3–4.8) 0.0 (0.0–0.0) 2.4 (-1.3–6.1) 2.4 (-1.3–6.1) 0.0 (0.0–0.0) 2.6 (-0.2–5.4) 2.6 (-0.2–5.4) 0.0 (0.0–0.0)

Varicella (≥ 1 dose) 0.4 (-0.9–1.7) 0.5 (-1.1–2.0) 0.0 (-1.0–0.9) -3.0 (-5.0–1.0) 1.2 (-1.5–3.8) -4.2 (-6.0–2.3) 2.4 (0.7–4.0) 0.1 (-1.9–2.0) 2.3 (1.2–3.4)

PCV

≥3 doses 0.0 (-1.3–1.4) 0.6 (-0.9–2.1) -0.6 (-1.3–0.2) -0.5 (-2.7–1.7) 1.7 (-0.8–4.2) -2.2 (-3.5–0.9) 0.3 (-1.4–2.0) -0.1 (-1.9–1.8) 0.4 (-0.5–1.3)

≥4 doses 0.6 (-1.2–2.4) 1.2 (-0.8–3.2) -0.6 (-1.6–0.4) -2.4 (-5.5–0.8) 2.1 (-1.2–5.4) -4.5 (-5.8–3.2) 2.4 (0.1–4.6) 0.7 (-1.8–3.2) 1.7 (0.2–3.1)

HepA

≥1 dose -0.1 (-1.7–1.5) 0.6 (-1.3–2.4) -0.7 (-1.7–0.4) -3.2 (-5.7–0.7) 3.6 (0.6–6.6) -6.8 (-8.7–4.9) 1.7 (-0.3–3.7) -1.2 (-3.5–1.1) 2.9 (1.6–4.1)

≥2 doses -0.9 (-3.1–1.3) 0.6 (-1.3–2.5) -1.5 (-3.8–0.7) -28.8 (-32.3–25.2) -0.7 (-3.9–2.4) -28.1 (-31.8–24.3) 15.0 (12.3–17.7) 1.4 (-1.1–3.9) 13.6 (10.8–16.5)

Rotavirus** -0.9 (-3.0–1.3) -0.8 (-3.0–1.3) 0.0 (-0.1–0.0) -0.4 (-4.1–3.3) -0.3 (-4.0–3.4) -0.1 (-0.2–0.0) -1.1 (-3.7–1.5) -1.1 (-3.7–1.5) 0.0 (0.0–0.1)

Combined 7-vaccine 

series†† -0.3 (-2.4–1.8) 0.3 (-2.0–2.5) -0.6 (-2.1–1.0) -5.5 (-9.1–1.9) 2.6 (-1.2–6.4) -8.1 (-10.6–5.5) 2.7 (0.1–5.3) -1.1 (-3.9–1.7) 3.8 (1.9–5.7)

No vaccinations 0.3 (0.1–0.6) NA NA 0.3 (0.0–0.7) NA NA 0.4 (0.0–0.7) NA NA

Abbreviations: CI = confidence interval; DTaP = diphtheria, tetanus toxoids, and acellular pertussis vaccine; HepA = hepatitis A vaccine; HepB = hepatitis B vaccine; Hib = Haemophilus influenzae type b 

conjugate vaccine; MMR = measles, mumps, and rubella vaccine; PCV = pneumococcal conjugate vaccine; UTD = up to date.

Bolded estimates of difference are statistically significant at p<0.05, when the absolute value of estimate is larger than the half-width of the 95% CI.
* The percentage point difference in NIS-Child vaccination coverage estimates from 2016 to 2017 (2017 estimate minus the 2016 estimate) was calculated overall, among children eligible for only 1 of the 

2 survey years (non-overlapping cohort, including children only from 2016 born January 2013–December 2013, and only from 2017 born June 2015–May 2016), and among children eligible in both survey 

years (bridging cohort, including children born January 2014–May 2015). Differences were also calculated for vaccinations received by the child’s age at vaccination assessment (UTD by 19 to 35 months), 

received before the child’s 19th month birthday (UTD by 19 months), and received during ages 19 months up to the child’s age at vaccination assessment (UTD during 19-34 months).

† Includes children who might have been vaccinated with diphtheria and tetanus toxoids vaccine or diphtheria, tetanus toxoids, and pertussis vaccine.

§ Hib Primary series: receipt of ≥2 or ≥3 doses, depending on product type received. Full series: receipt of ≥3 or ≥4 doses, depending on product type received (primary series and booster dose).

¶ One dose of HepB administered between birth and age 3 days.

** Rotavirus vaccine includes ≥2 or ≥3 doses, depending on the product type received (≥2 doses for Rotarix [RV1] and ≥3 doses for RotaTeq [RV5]). 

†† The combined 7-vaccine series (4:3:1:3*:3:1:4) includes ≥4 doses of DTaP, ≥3 doses of poliovirus vaccine, ≥1 dose of measles-containing vaccine, the full series of Hib (≥3 or ≥4 doses, depending on 

product type of vaccine), ≥3 doses of HepB, ≥1 dose of varicella vaccine, and ≥4 doses of PCV.