Table 2.

Estimates of piecewise terms in Poisson regression models for evaluation of effects of pneumococcal conjugate vaccines against pneumococcal infection on tympanostomy tube insertion among children.

	0–2 years old		2–5 years old		5–9 years old		9–17 years old
	β	se	β	se	β	se	β	se
Before 2005	0.004	0.014	0.052*	0.012	0.029*	0.009	0.037*	0.017
After 2005	−0.074*	0.021	0.041*	0.015	0.064*	0.012	0.039	0.020

^* P < 0.05.