Table 2.

Odds ratios with 95% confidence intervals, for being hospitalized with influenza in children with a risk condition during the influenza seasons in 2017–18 and 2018–19 in Norway

Risk category	Age groups (years)
	0–4	5–9	10–14	15–17	All ages
	OR (95% CI)	OR (95% CI)	OR (95% CI)	OR (95% CI)	OR (95% CI)
Influenza season 2017–18
Lung disease	3.0 (2.1–4.2)	4.5 (2.4–7.8)	2.6 (0.8–6.3)	5.8 (2.4–12.3)	4.0 (3.0–5.1)
Asthma	2.4 (1.5–3.7)	2.7 (1.0–6.0)	n.a.	6.3 (2.2–14.7)	2.9 (2.0–4.1)
Heart conditions	6.2 (2.0–14.7)	30.6 (12.0–65.6)	n.a.	n.a.	7.6 (3.9–13.3)
Neurological disease or sequelae	5.8 (2.5–11.5)	11.8 (5.5–22.5)	26.7 (14.0–47.8)	16.9 (7.3–34.6)	10.1 (7.2–13.9)
Epilepsy	6.8 (2.2–16.1)	16.2 (7.2–32.0)	25.1 (11.5–49.4)	23.4 (9.6–49.6)	12.1 (8.2–17.3)
Immunocompromised	11.4 (5.6–20.7)	44.5 (22.8–79.9)	35.1 (13.5–76.7)	n.a.	18.3 (12.3–26.4)
All patients with one or more risk condition					6.1 (5.0–7.4)
Influenza season 2018–19
Lung disease	4.1 (3.0–5.6)	4.4. (1.9–9.0)	n.a.	n.a.	4.7 (3.5–6.1)
Asthma	2.5 (1.6–3.9)	n.a.	n.a.	n.a.	2.4 (1.5–3.7)
Heart conditions	n.a.	n.a.	n.a.	n.a.	n.a.
Neurological disease or sequelae	11.0 (6.1–18.6)	17.6 (7.7–35.7)	n.a.	n.a.	7.0 (4.4–10.5)
Epilepsy	16.9 (8.6–30.1)	23.8 (9.8–49.9)	n.a.	n.a.	9.2 (5.6–14.4)
Immunocompromised	8.9 (4.0–17.1)	26.1 (8.2–64.1)	n.a.	53.9 (16.0–144.6)	13.6 (8.1–21.6)
All patients with one or more risk condition					6.8 (5.4–8.4)

n.a. = not applicable due to low numbers