Table 1:

Population Studies of the Severity of Invasive Haemophilus influenzae type a (Hia) Disease in Children

Study Author (Year)	Bender (2010)	McConnell (2007)	Millar (2005)	Rotondo (2013)
Study location (years)	Utah (1998–2008)	Canada(1996–2001)	Navajo, White Mountain Apache (1988–2003)	Canada (2000–2010)
Case ascertainment	Microbiology and hospital reports	Pediatric tertiary care centers	Active surveillance system	Public health laboratory passive surveillance
No. Isolates Hia / Serotyped Haemophilus isolates (%)	23/68 (34%)	25/147 (17%)	76/222 (34%)	72/128 (56%)
Estimated incidence per 100,000 children	0.8–2.6 (under 5 years)	2.3–418 (under 5 years)	20.2 (under 5 years)	4.6 (all ages)
Median age	11 months	8.5 months	12 months	-
Hia meningitis	13 (57%)	13 (52%)	38 (50%)	27 (37%)
Hospital admission	22 (96%)	25 (100%)	60 (79%)	62 (90%)
Intensive care admission	-	10 (40%)	-	-
Sequelae at discharge	-	6 (24%)	5 (7%)	-
Died	0 (0%)	4 (16%)	2 (3%)	4 (6%)