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

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

		All ages		Ages < 2		Ages 2–4		Ages 5–17
Period^a	Change	IRR^b (95% CI)^c	P^a	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
Early PCV7	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
Late PCV7	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
Early PCV13	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
Late PCV13	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

AOM acute otitis media, IRR incidence rate ratio, ITS interrupted time series, PCV pneumococcal conjugate vaccine
^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
^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
^cConfidence intervals have been adjusted for heteroscedasticity
^d^∗Coefficients statistically significant at P < 0.05

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