Table 2– Percentage of invasive pneumococcal disease (IPD) attributable to influenza-like illness activity in Denmark during 1977–2007, stratified by comorbidity and by clinical manifestation^#

	Age years
	15–39	≥40
All IPD
Low comorbidity (Charlson 0)	9.9 (6.0–13.0)	7.6 (5.1–11.6)
Medium/high comorbidity (Charlson ≥1)	0.3 (-8.4–9.7)	6.2 (4.3–9.3)
IPD with pneumonia diagnosis
Low comorbidity (Charlson 0)	11.2 (6.5–14.8)	7.8 (5.8–11.7)
Medium/high comorbidity (Charlson ≥1)	5.4 (-5.0–18.7)	6.5 (4.4–10.1)
IPD with other diagnosis
Low comorbidity (Charlson 0)	6.6 (-1.2–14.3)	6.9 (1.8–12.8)
Medium/high comorbidity (Charlson ≥1)	−6.6 (-25.7–7.6)	5.3 (2.5–8.9)

Data are presented as % (95% CI). ^#: N=13 882 cases of IPD; those aged <14 years were excluded from this analysis due to small numbers in the medium/high comorbidity group.