TABLE 2.

Estimated population influenza hospitalizations using the capture‐recapture method

	Observed influenza cases				C‐R estimated influenza cases $\widehat{\widehat{N}\left(95\%\mathrm{CI}\right)}$ a
	Clinical (M)	Research (n)	Matched (m)	Total (m + N 1 + N 2)
3‐ year total	308	313	284	337	339 (336, 342)
Age group
18–49 years	55	54	50	59	59 (58, 60)
50–64 years	94	95	85	104	105 (103, 107)
65–74 years	82	82	75	89	90 (88, 92)
75+	77	82	74	85	85 (84, 86)
Race b
White	191	199	179	211	212 (210, 214)
Black	103	100	92	111	112 (110, 114)
Sex
Female	191	195	175	211	213 (210, 216)
Male	117	118	109	126	127 (125, 129)
Season
2016–2017	84	82	77	89	89 (88, 90)
2017–2018	139	138	127	150	151 (149, 153)
2018–2019	85	93	80	98	99 (97, 101)
Vaccination status b
Unvaccinated	124	124	111	137	139 (136, 142)
Vaccinated	165	169	155	179	180 (178, 182)
Prior vaccination
No	167	167	153	181	182 (180, 184)
Yes	141	146	131	156	157 (155, 159)

Note. N ₁ = number of cases reported only in the clinical database; N ₂ = number of cases reported only in the research database.

^a

$\widehat{N}=\left(M*n\right)/m.$

^b Sum ≠ 337 due to missing data.