Table 1. Estimated rates of influenza-related hospitalization

Study [reference]	Years	Country	Category of admission	Annual rates of influenza-related hospitalization (per 100,000 persons)
Ortiz et al. [6]	2003–2009	United States	Respiratory failure	Overall: 2.7
				18–49 years: 0.8
				50–64 years: 4.0
				65–74 years: 8.7
				75–84 years: 16.5
				≥85 years: 27.9
Chan et al. [7]	1998–2012	Hong Kong	Influenza A	≥65 years: 183
			Influenza B	≥65 years: 35
Lemaitre et al. [8]	2010–2018	France	Pneumonia and influenza	Overall: 11.6–61.9
				≥65 years: 10.1–202.6
			Respiratory	Overall: 20.4–75.3
				≥65 years: 26.3–308.3
Hong et al. [9]	2009–2019	Korea	Influenza	20.5–169.9