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Table 3 Incidence rate ratio estimates from ITS analyses of monthly AOM episode incidence rates in commercially insured children aged < 18 years (1998–2018)

From: Incidence of acute otitis media in children in the United States before and after the introduction of 7- and 13-valent pneumococcal conjugate vaccines during 1998–2018

   All ages Ages < 2 Ages 2–4 Ages 5–17
Perioda Change IRRb
(95% CI)c
Pa IRR
(95% CI)
P IRR
(95% CI)
P IRR
(95% CI)
P
Pre-PCV7 Base Trend 1.005 (1.003–1.008) 0.001* 1.007 (1.002–1.013) 0.009* 1.006 (1.003–1.010) 0.001* 1.003 (0.998–1.007) 0.271
Early PCV7 Change in Level 0.888 (0.822–0.959) 0.003* 0.867 (0.794–0.946) 0.001* 0.887 (0.807–0.975) 0.013* 0.929 (0.812–1.063) 0.284
Change in Trend 0.991 (0.988–0.994) 0.001* 0.988 (0.983–0.994) 0.001* 0.990 (0.986–0.993) 0.001* 0.993 (0.989–0.998) 0.004*
Late PCV7 Change in Level 1.069 (0.982–1.164) 0.125 1.065 (0.976–1.162) 0.159 1.119 (1.029–1.218) 0.009* 1.044 (0.925–1.178) 0.488
Change in Trend 1.005 (1.003–1.007) 0.001* 1.005 (1.003–1.007) 0.001* 1.004 (1.002–1.006) 0.001* 1.007 (1.004–1.011) 0.001*
Early PCV13 Change in Level 1.046 (0.965–1.134) 0.270 0.978 (0.854–1.120) 0.747 1.076 (0.996–1.163) 0.064 1.090 (0.973–1.221) 0.138
Change in Trend 0.996 (0.993–0.998) 0.001* 0.998 (0.994–1.002) 0.374 0.997 (0.995–1.000) 0.030* 0.993 (0.990–0.996) 0.001*
Late PCV13 Change in Level 1.007 (0.936–1.083) 0.853 0.982 (0.904–1.068) 0.677 1.012 (0.936–1.094) 0.762 1.015 (0.921–1.118) 0.766
Change in Trend 1.003 (1.000–1.007) 0.069 1.002 (0.997–1.006) 0.401 1.003 (1.000–1.007) 0.092 1.003 (0.999–1.008) 0.117
  1. AOM acute otitis media, IRR incidence rate ratio, ITS interrupted time series, PCV pneumococcal conjugate vaccine
  2. aTime periods are defined as follows: Pre-PCV7: 1998–1999; Early PCV7: 2001–2005; Late PCV7: 2006–2009; Early PCV13: 2011–2013; Late PCV13: 2014–2018. Years 2000 and 2010 are considered transition years and were excluded from the model
  3. bAll estimates were obtained through a negative binomial model with a log link, controlling for seasonality using monthly indicators. IRR’s are the exponentiated regression coefficients and represent a multiplicative change. Model intercepts not shown
  4. cConfidence intervals have been adjusted for heteroscedasticity
  5. dCoefficients statistically significant at P < 0.05